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Chapter: AnyConnect VPN Client Connections

Chapter Contents

This section describes how to configure AnyConnect VPN Client Connections.

About the AnyConnect VPN Client

The Cisco AnyConnect Secure Mobility Client provides secure SSL and IPsec/IKEv2 connections to the ASA for remote users. Without a previously-installed client, remote users enter the IP address in their browser of an interface configured to accept SSL or IPsec/IKEv2 VPN connections. Unless the ASA is configured to redirect http:// requests to https://, users must enter the URL in the form https://<address>.

After entering the URL, the browser connects to that interface and displays the login screen. If the user satisfies the login and authentication, and the ASA identifies the user as requiring the client, it downloads the client that matches the operating system of the remote computer. After downloading, the client installs and configures itself, establishes a secure SSL or IPsec/IKEv2 connection and either remains or uninstalls itself (depending on the configuration) when the connection terminates.

In the case of a previously installed client, when the user authenticates, the ASA examines the revision of the client, and upgrades the client as necessary.

When the client negotiates an SSL VPN connection with the ASA, it connects using Transport Layer Security (TLS), and optionally, Datagram Transport Layer Security (DTLS). DTLS avoids latency and bandwidth problems associated with some SSL connections and improves the performance of real-time applications that are sensitive to packet delays.

The AnyConnect client can be downloaded from the ASA, or it can be installed manually on the remote PC by the system administrator. For more information about installing the client manually, see the appropriate release of the Cisco AnyConnect Secure Mobility Configuration Guide .

The ASA downloads the client based on the group policy or username attributes of the user establishing the connection. You can configure the ASA to automatically download the client, or you can configure it to prompt the remote user about whether to download the client. In the latter case, if the user does not respond, you can configure the ASA to either download the client after a timeout period or present the login page.

Requirements for AnyConnect

For the requirements of endpoint computers running the AnyConnect Secure Mobility Client, see the appropriate release of the Cisco AnyConnect Secure Mobility Release Notes.

Guidelines and Limitations for AnyConnect

  • The ASA does not verify remote HTTPS certificates.
  • Supported in single or multiple context mode. AnyConnect Apex license is required for remote-access VPN in multi-context mode. Although ASA does not specifically recognize an AnyConnect Apex license, it enforces licenses characteristics of an Apex license such as AnyConnect Premium licensed to the platform limit, AnyConnect for mobile, AnyConnect for Cisco VPN phone, and advanced endpoint assessment. Shared licensing, AnyConnect Essentials, failover license aggregation, and flex/time-based licenses are not supported.

Licensing Requirements for AnyConnect

NoteThis feature is not available on No Payload Encryption models.

VPN Licenses require an AnyConnect Plus or Apex license, available separately. See Cisco ASA Series Feature Licenses for maximum values per model.

If you start a clientless SSL VPN session and then start an AnyConnect client session from the portal, 1 session is used in total. However, if you start the AnyConnect client first (from a standalone client, for example) and then log into the clientless SSL VPN portal, then 2 sessions are used.

Configure AnyConnect Connections

This section describes prerequisites, restrictions, and detailed tasks to configure the ASA to accept AnyConnect VPN client connections.

Configure the ASA to Web-Deploy the Client

The section describes the steps to configure the ASA to web-deploy the AnyConnect client.

Before you begin

Copy the client image package to the ASA using TFTP or another method.

Procedure

Step 1Identify a file on flash as an AnyConnect client package file.The ASA expands the file in cache memory for downloading to remote PCs. If you have multiple clients, assign an order to the client images with the order argument.The ASA downloads portions of each client in the order you specify until it matches the operating system of the remote PC. Therefore, assign the lowest number to the image used by the most commonly-encountered operating system.anyconnect image filename orderExample: hostname(config-webvpn)# anyconnect image anyconnect-win-2.3.0254-k9.pkg 1 hostname(config-webvpn)# anyconnect image anyconnect-macosx-i386-2.3.0254-k9.pkg 2 hostname(config-webvpn)# anyconnect image anyconnect-linux-2.3.0254-k9.pkg 3 Note You must issue the anyconnect enable command after configuring the AnyConnect images with the anyconnect image command. If you do not enable AnyConnect, it will not operate as expected, and show webvpn anyconnectconsiders the SSL VPN client as not enabled rather than listing the installed AnyConnect packages.
Step 2Enable SSL on an interface for clientless or AnyConnect SSL connections.enable interfaceExample:hostname(config)# webvpn hostname(config-webvpn)# enable outside
Step 3Without issuing this command, AnyConnect does not function as expected, and a show webvpn anyconnect command returns that the “SSL VPN is not enabled,” instead of listing the installed AnyConnect packages.anyconnect enable
Step 4(Optional) Create an address pool. You can use another method of address assignment, such as DHCP and/or user-assigned addressing.ip local pool poolname startaddr-endaddr mask maskExample:hostname(config)# ip local pool vpn_users 209.165.200.225-209.165.200.254 mask 255.255.255.224
Step 5Assign an address pool to a tunnel group.address-pool poolnameExample:hostname(config)# tunnel-group telecommuters general-attributes hostname(config-tunnel-general)# address-pool vpn_users
Step 6Assign a default group policy to the tunnel group.default-group-policy namehostname(config-tunnel-general)# default-group-policy sales
Step 7Enable the display of the tunnel-group list on the clientless portal and AnyConnect GUI login page. The list of aliases is defined by the group-alias name enable command.group-alias name enableExample:hostname(config)# tunnel-group telecommuters webvpn-attributes hostname(config-tunnel-webvpn)# group-alias sales_department enable
Step 8Specify the AnyConnect clients as a permitted VPN tunneling protocol for the group or user.tunnel-group-list enableExample:hostname(config)# webvpn hostname(config-webvpn)# tunnel-group-list enable
Step 9Specify SSL as a permitted VPN tunneling protocol for the group or user. You can also specify additional protocols. For more information, see the vpn-tunnel-protocol command in the command reference.vpn-tunnel-protocolExample:hostname(config)# group-policy sales attributes hostname(config-group-policy)# webvpn hostname(config-group-webvpn)# vpn-tunnel-protocol

What to do next

For more information about assigning users to group policies, see Chapter 6, Configuring Connection Profiles, Group Policies, and Users.

Enable Permanent Client Installation

Enabling permanent client installation disables the automatic uninstalling feature of the client. The client remains installed on the remote computer for subsequent connections, reducing the connection time for the remote user.

To enable permanent client installation for a specific group or user, use the anyconnect keep-installer command from group-policy or username webvpn modes.

The default is that permanent installation of the client is enabled. The client remains on the remote computer at the end of the session. The following example configures the existing group-policy sales to remove the client on the remote computer at the end of the session:

hostname(config)# group-policy sales attributes
hostname(config-group-policy)# webvpn
hostname(config-group-policy)# anyconnect keep-installer installed none

Configure DTLS

Datagram Transport Layer Security (DTLS) allows the AnyConnect client establishing an SSL VPN connection to use two simultaneous tunnels—an SSL tunnel and a DTLS tunnel. Using DTLS avoids latency and bandwidth problems associated with SSL connections and improves the performance of real-time applications that are sensitive to packet delays.

Before you begin

See, Configure Advanced SSL Settings to configure DTLS on this headend, and which version of DTLS is used.

In order for DTLS to fall back to a TLS connection, Dead Peer Detection (DPD) must be enabled. If you do not enable DPD, and the DTLS connection experiences a problem, the connection terminates instead of falling back to TLS. For more information on DPD, see Configure Dead Peer Detection.

Procedure

Step 1Specify DTLS options for AnyConnect VPN connections:Enable SSL and DTLS on the interface in webvpn mode.By default, DTLS is enabled when SSL VPN access is enabled on an interface.hostname(config)# webvpn hostname(config-webvpn)# enable outside Disable DTLS for all AnyConnect client users with the enable interface tls-onlycommand in webvpn configuration mode.If you disable DTLS, SSL VPN connections connect with an SSL VPN tunnel only.hostname(config)# webvpn hostname(config-webvpn)# enable outside tls-only Configure the ports for SSL and DTLS using the port and dtls port commands.hostname(config)# webvpn hostname(config-webvpn)# enable outside hostname(config-webvpn)# port 555 hostname(config-webvpn)# dtls port 556
Step 2Specify DTLS options for specific group policies.Enable DTLS for specific groups or users with the anyconnect ssl dtls command in group policy webvpn or username webvpn configuration mode.hostname(config)# group-policy sales attributes hostname(config-group-policy)# webvpn hostname(config-group-webvpn)# anyconnect ssl dtls enable If desired, enable DTLS compression using the anyconnect dtls compression command.hostname(config-group-webvpn)# anyconnect dtls compression lzs

Prompt Remote Users

Procedure

You can enable the ASA to prompt remote SSL VPN client users to download the client with the anyconnect ask command from group policy webvpn or username webvpn configuration modes:[no] anyconnect ask {none | enable [default {webvpn | } timeout value]}anyconnect enable prompts the remote user to download the client or go to the clientless portal page and waits indefinitely for user response.anyconnect ask enable default immediately downloads the client.anyconnect ask enable default webvpn immediately goes to the portal page.anyconnect ask enable default timeout value prompts the remote user to download the client or go to the clientless portal page and waits the duration of value before taking the default action—downloading the client.anyconnect ask enable default clientless timeout value prompts the remote user to download the client or go to the clientless portal page, and waits the duration of valuebefore taking the default action—displaying the clientless portal page.

The figure below shows the prompt displayed to remote users when either default anyconnect timeoutvalue or default webvpn timeoutvalue is configured:

Figure 1. Prompt Displayed to Remote Users for SSL VPN Client Download

Example

The following example configures the ASA to prompt the user to download the client or go to the clientless portal page and wait 10 seconds for a response before downloading the client:

hostname(config-group-webvpn)# anyconnect ask enable default anyconnect timeout 10

Enable AnyConnect Client Profile Downloads

You enable Cisco AnyConnect Secure Mobility client features in the AnyConnect profiles—XML files that contain configuration settings for the core client with its VPN functionality and for the optional client modules. The ASA deploys the profiles during AnyConnect installation and updates. Users cannot manage or modify profiles.

You can configure a profile using the AnyConnect profile editor, a convenient GUI-based configuration tool launched from ASDM or ISE. The AnyConnect software package for Windows includes the editor, which activates when you load the AnyConnect package on the chosen headend device and specify it as an AnyConnect client image.

We also provide a standalone version of the profile editor for Windows that you can use as an alternative to the profile editor integrated with ASDM or ISE. If you are predeploying the client, you can use the standalone profile editor to create profiles for the VPN service and other modules that you deploy to computers using your software management system.

For more information on the AnyConnect client and its Profile Editor, see the appropriate release of the Cisco AnyConnect Secure Mobility Configuration Guide .

NoteThe AnyConnect client protocol defaults to SSL. To enable IPsec IKEv2, you must configure the IKEv2 settings on the ASA and also configure IKEv2 as the primary protocol in the client profile. The IKEv2enabled profile must be deployed to the endpoint computer; otherwise the client attempts to connect using SSL.

Procedure

Step 1Use the profile editor from ASDM/ISE or the standalone profile editor to create a profile.
Step 2Load the profile file into flash memory on the ASA using tftp or another method.
Step 3Use the anyconnect profiles command from webvpn configuration mode to identify the file as a client profile to load into cache memory.Example:The following example specifies the files sales_hosts.xml and engineering_hosts.xml as profiles: asa1(config-webvpn)# anyconnect profiles sales disk0:/sales_hosts.xml asa1(config-webvpn)# anyconnect profiles engineering disk0:/engineering_hosts.xml The profiles are now available to group policies.View the profiles loaded in cache memory using the dir cache:stc/profilescommand: hostname(config-webvpn)# dir cache:/stc/profiles Directory of cache:stc/profiles/ 0 ---- 774 11:54:41 Nov 22 2006 engineering.xml 0 ---- 774 11:54:29 Nov 22 2006 sales.xml 2428928 bytes total (18219008 bytes free) hostname(config-webvpn)#
Step 4Enter group policy webvpn configuration mode and specify a client profile for a group policy with the anyconnect profiles command:Example:You can enter the anyconnect profiles value command followed by a question mark (? ) to view the available profiles. For example: asa1(config-group-webvpn)# anyconnect profiles value ? config-group-webvpn mode commands/options: Available configured profile packages: engineering sales The next example configures the group policy to use the profile sales with the client profile type vpn: asa1(config-group-webvpn)# anyconnect profiles value sales type vpn asa1(config-group-webvpn)#

Enable AnyConnect Client Deferred Upgrade

Deferred Upgrade allows the AnyConnect user to delay download of a client upgrade. When a client update is available, AnyConnect opens a dialog asking the user if they would like to update, or to defer the upgrade. This upgrade dialog will not appear unless you have AutoUpdate set to Enabled in the AnyConnect profile setting.

Deferred Upgrade is enabled by adding custom attribute types and named values to the ASA; then referencing and configuring those attributes in a group policy.

The following custom attributes support Deferred Upgrade:

Custom Attribute TypeValid 
ValuesDefault ValueNotes
DeferredUpdateAllowedtrue
falsefalseTrue enables deferred update. If deferred update is disabled (false), the settings below are ignored.
DeferredUpdateMinimumVersionx.y.z0.0.0Minimum version of AnyConnect that must be installed for updates to be deferrable.The minimum version check applies to all modules enabled on the headend. If any enabled module (including VPN) is not installed or does not meet the minimum version, then the connection is not eligible for deferred update.If this attribute is not specified, then a deferral prompt is displayed (or auto-dismissed) regardless of the version installed on the endpoint.
DeferredUpdateDismissTimeout0-300
(seconds)none
(disabled)Number of seconds that the deferred upgrade prompt is displayed before being dismissed automatically. This attribute only applies when a deferred update prompt is to be displayed (the minimum version attribute is evaluated first).If this attribute is missing, then the auto-dismiss feature is disabled, and a dialog is displayed (if required) until the user responds.Setting this attribute to zero allows automatic deferral or upgrade to be forced based on:The installed version and the value of DeferredUpdateMinimumVersion.The value of DeferredUpdateDismissResponse.
DeferredUpdateDismissResponsedefer
updateupdateAction to take when DeferredUpdateDismissTimeout occurs.

Procedure

Step 1Create the custom attribute types with the anyconnnect-custom-attr command in webvpn configuration mode:[no] anyconnect-custom-attr attr-type [description description ]Example:The following example shows how to add the custom attribute types DeferredUpdateAllowed and DeferredUpdateDismissTimeout: hostame(config-webvpn)# anyconnect-custom-attr DeferredUpdateAllowed description Indicates if the deferred update feature is enabled or not hostame(config-webvpn)# anyconnect-custom-attr DeferredUpdateDismissTimeout
Step 2Add named values for custom attributes with the anyconnect-custom-data command in global configuration mode. For attributes with long values, you can provide a duplicate entry, and it allows concatenation. However, with a duplicate configuration entry, the Defer Update dialog will not appear, and a user cannot defer the upgrade; instead, the upgrade happens automatically.[no] anyconnect-custom-data attr-type attr-name attr-valueExample:The following example shows how to add a named value for the custom attribute type DeferredUpdateDismissTimeout and for enabling DeferredUpdateAllowed: hostname(config)# anyconnect-custom-data DeferredUpdateDismissTimeout def-timeout 150 hostname(config)# anyconnect-custom-data DeferredUpdateAllowed def-allowed true
Step 3Add or remove the custom attribute named values to a group policy using theanyconnect-custom command:anyconnect-custom attr-type value attr-nameanyconnect-custom attr-type noneno anyconnect-custom attr-typeExample:The following example shows how to enable Deferred Update for the group policy named sales and set the timeout to 150 seconds: hostname(config)# group-policy sales attributes hostname(config-group-policy)# anyconnect-custom DeferredUpdateAllowed value def-allowed hostname(config-group-policy)# anyconnect-custom DeferredUpdateDismissTimeout value def-timeout

Enable DSCP Preservation

By setting another custom attribute, you can control Differentiated Services Code Point (DSCP) on Windows or OS X platforms for DTLS connections only. Enabling DSCP preservation allows devices to prioritize latency sensitive traffic; the router takes into account whether this is set and marks prioritized traffic to improve outbound connection quality.

Procedure

Step 1Create the custom attribute types with the anyconnect-custom-attrcommand in webvpn configuration mode:[no] anyconnect-custom-attr DSCPPreservationAllowed description Set to control Differentiated Services Code Point (DSCP) on Windows or OS X platforms for DTLS connections only.
Step 2Add named values for custom attributes with the anyconnect-custom-datacommand in global configuration mode:[no] anyconnect-custom-data DSCPPreservationAllowed trueNote By default, AnyConnect performs DSCP preservation (true). To disable it, set the custom attributes to false on the headend and reinitiate the connection.

Enable Additional AnyConnect Client Features

To minimize download time, the client only requests downloads (from the ASA or ISE) of the core modules that it needs. As additional features become available for the AnyConnect client, you need to update the remote clients in order for them to use the features.

To enable new features, you must specify the new module names using the anyconnect modules command from group policy webvpn or username webvpn configuration mode:

[no]anyconnect modules {none | value string}

Separate multiple strings with commas.

Enable Start Before Logon

Start Before Logon (SBL) allows login scripts, password caching, drive mapping, and more, for the AnyConnect client installed on a Windows PC. For SBL, you must enable the ASA to download the module which enables graphical identification and authentication (GINA) for the AnyConnect client. The following procedure shows how to enable SBL:

Procedure

Step 1Enable the ASA to download the GINA module for VPN connection to specific groups or users using the anyconnect modules vpngina command from group policy webvpn or username webvpn configuration modes.Example:In the following example, the user enters group-policy attributes mode for the group policy telecommuters, enters webvpn configuration mode for the group policy, and specifies the string vpngina :hostname(config)# group-policy telecommuters attributes hostname(config-group-policy)# webvpn hostame(config-group-webvpn)#anyconnect modules value vpngina
Step 2Retrieve a copy of the client profiles file (AnyConnectProfile.tmpl).
Step 3Edit the profiles file to specify that SBL is enabled. The example below shows the relevant portion of the profiles file (AnyConnectProfile.tmpl) for Windows:<Configuration> <ClientInitialization> <UseStartBeforeLogon>false</UseStartBeforeLogon> </ClientInitialization> The <UseStartBeforeLogon> tag determines whether the client uses SBL. To turn SBL on, replace false with true. The example below shows the tag with SBL turned on:<ClientInitialization> <UseStartBeforeLogon>true</UseStartBeforeLogon> </ClientInitialization>
Step 4Save the changes to AnyConnectProfile.tmpl and update the profile file for the group or user on the ASA using the  profile command from webvpn configuration mode. For example:asa1(config-webvpn)#anyconnect profiles sales disk0:/sales_hosts.xml

Translating Languages for AnyConnect User Messages

The ASA provides language translation for the portal and screens displayed to users that initiate browser-based, Clientless SSL VPN connections, as well as the interface displayed to Cisco AnyConnect VPN Client users.

This section describes how to configure the ASA to translate these user messages.

Understand Language Translation

Functional areas and their messages that are visible to remote users are organized into translation domains. All messages displayed on the user interface of the Cisco AnyConnect VPN Client are located in the AnyConnect domain.

The software image package for the ASA includes a translation table template for the AnyConnect domain. You can export the template, which creates an XML file of the template at the URL you provide. The message fields in this file are empty. You can edit the messages and import the template to create a new translation table object that resides in flash memory.

You can also export an existing translation table. The XML file created displays the messages you edited previously. Reimporting this XML file with the same language name creates an new version of the translation table object, overwriting previous messages. Changes to the translation table for the AnyConnect domain are immediately visible to AnyConnect client users.

Create Translation Tables

The following procedure describes how to create translation tables for the AnyConnect domain:

Procedure
Step 1Export a translation table template to a computer with the export webvpn translation-table command from privileged EXEC mode.In the following example, the show import webvpn translation-table command shows available translation table templates and tables. hostname# show import webvpn translation-table Translation Tables' Templates: customization AnyConnect PortForwarder url-list webvpn Citrix-plugin RPC-plugin Telnet-SSH-plugin VNC-plugin Translation Tables: Then the user exports the translation table for the AnyConnect translation domain. The filename of the XML file created is named client and contains empty message fields: hostname# export webvpn translation-table AnyConnect template tftp://209.165.200.225/client In the next example, the user exports a translation table named zh, which was previously imported from a template. zh is the abbreviation by Microsoft Internet Explorer for the Chinese language. hostname# export webvpn translation-table customization language zh tftp://209.165.200.225/chinese_client
Step 2Edit the Translation Table XML file. The following example shows a portion of the AnyConnect template. The end of this output includes a message ID field (msgid) and a message string field (msgstr) for the message Connected, which is displayed on the AnyConnect client GUI when the client establishes a VPN connection. The complete template contains many pairs of message fields: # SOME DESCRIPTIVE TITLE. # Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER # This file is distributed under the same license as the PACKAGE package. # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR. # #, fuzzy msgid "" msgstr "" "Project-Id-Version: PACKAGE VERSION\n" "Report-Msgid-Bugs-To: \n" "POT-Creation-Date: 2006-11-01 16:39-0700\n" "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n" "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n" "Language-Team: LANGUAGE <LL@li.org>\n" "MIME-Version: 1.0\n" "Content-Type: text/plain; charset=CHARSET\n" "Content-Transfer-Encoding: 8bit\n" #: C:\cygwin\home\<user>\cvc\main\Api\AgentIfc.cpp:23 #: C:\cygwin\home\<user>\cvc\main\Api\check\AgentIfc.cpp:22 #: C:\cygwin\home\<user>\cvc\main\Api\save\AgentIfc.cpp:23 #: C:\cygwin\home\<user>\cvc\main\Api\save\AgentIfc.cpp~:20 #: C:\cygwin\home\<user>\cvc\main\Api\save\older\AgentIfc.cpp:22 msgid "Connected" msgstr "" The msgid contains the default translation. The msgstr that follows msgid provides the translation. To create a translation, enter the translated text between the quotes of the msgstr string. For example, to translate the message “Connected” with a Spanish translation, insert the Spanish text between the quotes: msgid "Connected" msgstr "Conectado" Be sure to save the file.
Step 3Import the translation table using the import webvpn translation-table command from privileged EXEC mode. Be sure to specify the name of the new translation table with the abbreviation for the language that is compatible with the browser.In the following example, the XML file is imported es-us—the abbreviation used by Microsoft Internet Explorer for Spanish spoken in the United States.hostname# import webvpn translation-table AnyConnect language es-us tftp://209.165.200.225/client hostname# !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! hostname# show import webvpn translation-table Translation Tables' Templates: AnyConnect PortForwarder customization keepout url-list webvpn Citrix-plugin RPC-plugin Telnet-SSH-plugin VNC-plugin Translation Tables: es-us AnyConnect

Remove Translation Tables

If you no longer need a translation table, you can remove it.

Procedure
Step 1List the existing translation tables.In the following example, the show import webvpn translation-table command shows available translation table templates and tables. Various tables are available for French (fr), Japanese (ja), and Russian (ru). hostname# show import webvpn translation-table Translation Tables' Templates: AnyConnect PortForwarder banners csd customization url-list webvpn Translation Tables: fr PortForwarder fr AnyConnect fr customization fr webvpn ja PortForwarder ja AnyConnect ja customization ja webvpn ru PortForwarder ru customization ru webvpn
Step 2Remove the unwanted translation table.revert webvpn translation-table translationdomain language languageWhere translationdomain is the domain listed on the right in the Translation Tables listing shown above, and language is the 2-character language name.You must remove each table individually. You cannot remove all of the tables for a given language with one command.For example, to remove the French translation table for AnyConnect: ciscoasa# revert webvpn translation-table anyconnect language fr ciscoasa#

Configuring Advanced AnyConnect SSL Features

The following section describes advanced features that fine-tune AnyConnect SSL VPN connections.

Enable Rekey

When the ASA and the AnyConnect client perform a rekey on an SSL VPN connection, they renegotiate the crypto keys and initialization vectors, increasing the security of the connection.

To enable the client to perform a rekey on an SSL VPN connection for a specific group or user, use the anyconnect ssl rekey command from group-policy or username webvpn modes.

[no]anyconnect ssl rekey {method {new-tunnel | none | ssl} | time minutes}

  • method new-tunnel specifies that the client establishes a new tunnel during rekey.
  • method ssl specifies that the client establishes a new tunnel during rekey.
  • method none disables rekey.
  • time minutes specifies the number of minutes from the start of the session, or from the last rekey, until the rekey takes place, from 1 to 10080 (1 week).
NoteConfiguring the rekey method as ssl or new-tunnel specifies that the client establishes a new tunnel during rekey instead of the SSL renegotiation taking place during the rekey. See the command reference for a history of the anyconnect ssl rekey command.

In the following example, the client is configured to renegotiate with SSL during rekey, which takes place 30 minutes after the session begins, for the existing group-policy sales:

hostname(config)# group-policy sales attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# anyconnect ssl rekey method ssl
hostname(config-group-webvpn)# anyconnect ssl rekey time 30

Configure Dead Peer Detection

Dead Peer Detection (DPD) ensures that the ASA (gateway) or the client can quickly detect a condition where the peer is not responding, and the connection has failed. To enable dead peer detection (DPD) and set the frequency with which either the AnyConnect client or the ASA gateway performs DPD, do the following:

Before you begin
  • This feature applies to connectivity between the ASA gateway and the AnyConnect SSL VPN Client only. It does not work with IPsec since DPD is based on the standards implementation that does not allow padding, and CLientless SSL VPN is not supported.
  • If you enable DTLS, enable Dead Peer Detection (DPD) also. DPD enables a failed DTLS connection to fallback to TLS. Otherwise, the connection terminates.
  • When DPD is enabled on the ASA, you can use the Optimal MTU (OMTU) function to find the largest endpoint MTU at which the client can successfully pass DTLS packets. Implement OMTU by sending a padded DPD packet to the maximum MTU. If a correct echo of the payload is received from the head end, the MTU size is accepted. Otherwise, the MTU is reduced, and the probe is sent again until the minimum MTU allowed for the protocol is reached.
Procedure
Step 1Go to the desired group policy.Enter group policy or username webvpn mode:hostname(config)# group-policy group-policy-name attributes hostname(config-group-policy)# webvpn hostname(config-group-webvpn)# Or,hostname# username username attributes hostname(config-username)# webvpn hostname (config-username-webvpn #
Step 2Set Gateway Side Detection.Use the [no] anyconnect dpd-interval {[gateway {seconds | none}] command.The gateway refers to the ASA. You enable DPD and specify the interval with which the ASA waits for any packet from the client as a range of from 30 (default) to 3600 seconds (1 hour). A value of 300 is recommended. If no packets are received within that interval, the ASA performs the DPD test with three attempts at the same interval. If the ASA does not receive a response from the client, it tears down the TLS/DTLS tunnel.Note Specifying none disables the DPD testing that the ASA performs. Use no anyconnect dpd-interval to remove this command from the configuration.Specifying none disables the DPD testing that the ASA performs. Use no anyconnect dpd-interval to remove this command from the configuration.
Step 3Set Client Side Detection.Use the [no] anyconnect dpd-interval {[client {seconds | none}]} command.The client refers to the AnyConnect client. You enable DPD and specify the frequency with which the client performs the DPD test as a range of from 30 (default) to 3600 seconds (1 hour). A value of 300 is recommended.Specifying client none disables DPD performed by the client. Use no anyconnect dpd-interval to remove this command from the configuration.
Example

The following example sets the frequency of DPD performed by the ASA to 30 seconds, and the frequency of DPD performed by the client set to 10 seconds for the existing group-policy sales:

hostname(config)# group-policy sales attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# anyconnect dpd-interval gateway 30
hostname(config-group-webvpn)# anyconnect dpd-interval client 10

Enable Keepalive

You can adjust the frequency of keepalive messages to ensure that an SSL VPN connection through a proxy, firewall, or NAT device remains open, even if the device limits the time that the connection can be idle. Adjusting the frequency also ensures that the client does not disconnect and reconnect when the remote user is not actively running a socket-based application, such as Microsoft Outlook or Microsoft Internet Explorer.

Keepalives are enabled by default. If you disable keepalives, in the event of a failover, SSL VPN client sessions are not carried over to the standby device.

To set the frequency of keepalive messages, use the  keepalive command from group-policy webvpn or username webvpn configuration mode: Use the no form of the command to remove the command from the configuration and cause the value to be inherited:

[no] anyconnect ssl keepalive {none | seconds}

  • none disables client keepalive messages.
  • seconds enables the client to send keepalive messages, and specifies the frequency of the messages in the range of 15 to 600 seconds.

In the following example, the ASA is configured to enable the client to send keepalive messages with a frequency of 300 seconds (5 minutes), for the existing group-policy sales:

hostname(config)# group-policy sales attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# anyconnect ssl keepalive 300

Use Compression

Compression increases the communications performance between the ASA and the client by reducing the size of the packets being transferred for low-bandwidth connections. By default, compression for all SSL VPN connections is enabled on the ASA, both at the global level and for specific groups or users.

NoteWhen implementing compression on broadband connections, you must carefully consider the fact that compression relies on loss-less connectivity. This is the main reason that it is not enabled by default on broadband connections.

Compression must be turned-on globally using the compression command from global configuration mode, and then it can be set for specific groups or users with the anyconnect ssl compression command in group-policy and username webvpn modes.

Changing Compression Globally

To change the global compression settings, use the anyconnect ssl compression command from global configuration mode. To remove the command from the configuration, use the noform of the command.

In the following example, compression is disabled for all SSL VPN connections globally:

hostname(config)# no compression
Changing Compression for Groups and Users

To change compression for a specific group or user, use the anyconnect ssl compression command in the group-policy and username webvpn modes:

[no] anyconnect ssl compression {deflate | none}

By default, for groups and users, SSL compression is set to deflate (enabled).

To remove the anyconnect ssl compression command from the configuration and cause the value to be inherited from the global setting, use the no form of the command:

In the following example, compression is disabled for the group-policy sales:

hostname(config)# group-policy sales attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# no anyconnect ssl compression none

Adjust MTU Size

You can adjust the MTU size (from 576 to 1406 bytes) for SSL VPN connections established by the client with the anyconnect mtu command from group policy webvpn or username webvpn configuration mode:

  • [no] anyconnect mtu size

This command affects only the AnyConnect client. The legacy Cisco SSL VPN Client () is not capable of adjusting to different MTU sizes. Also, client connections established in SSL and those established in SSL with DTLS are impacted by this command.

The default for this command in the default group policy is no anyconnect mtu . The MTU size is adjusted automatically based on the MTU of the interface that the connection uses, minus the IP/UDP/DTLS overhead.

You may receive an “MTU configuration sent from the secure gateway is too small” message, for example, when running the ISE Posture AnyConnect module. If you enter anyconnect mtu 1200 along with anyconnect ssl df-bit-ignore disable, you can avoid these system scan errors.

Example

The following example configures the MTU size to 1200 bytes for the group policy telecommuters:

hostname(config)# group-policy telecommuters attributes
hostname(config-group-policy)# webvpn
hostname(config-group-webvpn)# anyconnect mtu 1200

Update AnyConnect Client Images

You can update the client images on the ASA at any time using the following procedure:

Procedure

Step 1Copy the new client images to the ASA using the copy command from privileged EXEC mode, or using another method.
Step 2If the new client image files have the same filenames as the files already loaded, reenter the anyconnect image command that is in the configuration. If the new filenames are different, uninstall the old files using the [no]anyconnect imageimage command. Then use the anyconnect image command to assign an order to the images and cause the ASA to load the new images.

Enable IPv6 VPN Access

If you want to configure IPv6 access, you must use the command-line interface. Release 9.0(x) of the ASA adds support for IPv6 VPN connections to its outside interface using SSL and IKEv2/IPsec protocols.

You enable IPv6 access using the ipv6 enable command as part of enabling SSL VPN connections. The following is an example for an IPv6 connection that enables IPv6 on the outside interface:

hostname(config)# interface GigabitEthernet0/0
hostname(config-if)# ipv6 enable

To enable IPV6 SSL VPN, do the following general actions:

  1. Enable IPv6 on the outside interface.
  2. Enable IPv6 and an IPv6 address on the inside interface.
  3. Configure an IPv6 address local pool for client assigned IP Addresses.
  4. Configure an IPv6 tunnel default gateway.

Procedure

Step 1Configure Interfaces: interface GigabitEthernet0/0 nameif outside security-level 0 ip address 192.168.0.1 255.255.255.0 ipv6 enable ; Needed for IPv6. ! interface GigabitEthernet0/1 nameif inside security-level 100 ip address 10.10.0.1 255.255.0.0 ipv6 address 2001:DB8::1/32 ; Needed for IPv6. ipv6 enable ; Needed for IPv6.
Step 2Configure an ‘ipv6 local pool’ (used for IPv6 address assignment):ipv6 local pool ipv6pool 2001:DB8:1:1::5/32 100 ; Use your IPv6 prefix here Note You can configure the ASA to assign an IPv4 address, an IPv6 address, or both an IPv4 and an IPv6 address to an AnyConnect client by creating internal pools of addresses on the ASA or by assigning a dedicated address to a local user on the ASA.
Step 3Add the ipv6 address pool to your tunnel group policy (or group-policy):tunnel-group YourTunGrp1 general-attributes ipv6-address-pool ipv6pool Note You must also configure an IPv4 address pool here as well (using the ‘address-pool’ command).
Step 4Configure an IPv6 tunnel default gateway:ipv6 route inside ::/0 X:X:X:X::X tunneled

Monitor AnyConnect Connections

To view information about active sessions, use the show vpn-sessiondb command:

CommandPurpose
show vpn-sessiondbDisplays information about active sessions.
vpn-sessiondb logoffLogs off VPN sessions.
show vpn-sessiondb anyconnectEnhances the VPN session summary to show OSPFv3 session information.
show vpn-sessiondb ratio encryptionShows the number of tunnels and percentages for the Suite B algorithms (such as AES-GCM-128, AES-GCM-192, AES-GCM-256, AES-GMAC-128, and so on).

Example

The Inactivity field shows the elapsed time since an AnyConnect session lost connectivity. If the session is active, 00:00m:00s appears in this field.


hostname# show vpn-sessiondb 

Session Type: SSL VPN Client

Username     : lee
Index        : 1                      IP Addr      : 209.165.200.232
Protocol     : SSL VPN Client         Encryption   : 3DES
Hashing      : SHA1                   Auth Mode    : userPassword
TCP Dst Port : 443                    TCP Src Port : 54230
Bytes Tx     : 20178                  Bytes Rx     : 8662
Pkts Tx      : 27                     Pkts Rx      : 19
Client Ver   : Cisco STC 1.1.0.117
Client Type  : Internet Explorer
Group        : DfltGrpPolicy
Login Time   : 14:32:03 UTC Wed Mar 20 2007
Duration     : 0h:00m:04s
Inactivity			 : 0h:00m:04s
Filter Name  :

hostname# vpn-sessiondb logoff 
INFO: Number of sessions of type "" logged off : 1

hostname# vpn-sessiondb logoff name tester
Do you want to logoff the VPN session(s)? [confirm]
INFO: Number of sessions with name "tester" logged off : 1

Log Off AnyConnect VPN Sessions

To log off all VPN sessions, use the vpn-sessiondb logoff command in global configuration mode:

The following example logs off all VPN sessions:

hostname# vpn-sessiondb logoff 
INFO: Number of sessions of type “” logged off : 1

You can log off individual sessions using either the name argument or the index argument:

  • vpn-sessiondb logoff name name
  • vpn-sessiondb logoff index index

The sessions that have been inactive the longest time are marked as idle (and are automatically logged off) so that license capacity is not reached and new users can log in. If the session resumes at a later time, it is removed from the inactive list.

You can find both the username and the index number (established by the order of the client images) in the output of the show vpn-sessiondb anyconnect command. The following examples shows the username lee and index number 1.


hostname# show vpn-sessiondb anyconnect

Session Type: AnyConnect

Username     : lee                    Index        : 1
Assigned IP  : 192.168.246.1           Public IP    : 10.139.1.2
Protocol     : AnyConnect-Parent SSL-Tunnel DTLS-Tunnel
License      : AnyConnect Premium
Encryption   : RC4 AES128             Hashing      : SHA1
Bytes Tx     : 11079                  Bytes Rx     : 4942
Group Policy : EngPolicy            Tunnel Group : EngGroup
Login Time   : 15:25:13 EST Fri Jan 28 2011
Duration     : 0h:00m:15s
Inactivity   : 0h:00m:00s
NAC Result   : Unknown
VLAN Mapping : N/A                    VLAN         : none

The following example terminates the session using the name option of the vpn-session-db logoff command:


hostname# vpn-sessiondb logoff name lee
Do you want to logoff the VPN session(s)? [confirm]
INFO: Number of sessions with name “lee” logged off : 1

hostname#

Feature History for AnyConnect Connections

The following table lists the release history for this feature.

Feature NameReleasesFeature Information
AnyConnect Connections7.2(1)The following commands were introduced or modified: authentication eap-proxy, authentication ms-chap-v1, authentication ms-chap-v2, authentication pap, l2tp tunnel hello, vpn-tunnel-protocol l2tp-ipsec.
IPsec IKEv28.4(1)IKEv2 was added to support IPsec IKEv2 connections for AnyConnect and LAN-to-LAN.