Contents

Introduction

Prerequisites

Requirements

Components Used

Background Information

Network Diagram

Configure

Authentication and Authorization of users with the Local Database

Example: AnyConnect Profile Download Configuration

Disable the AnyConnect downloader capability (optional).

AnyConnect XML profile delivery

Communication flow

IKEv2 and EAP exchange

Verify

Troubleshoot

Introduction

This document describes how to configure a Cisco IOS® / Cisco IOS® XE headend for access via AnyConnect IKEv2 / EAP authentication with local user database.

Prerequisites

Requirements

Cisco recommends that you have knowledge of these topics:

- IKEv2 protocol

Components Used

The information in this document is based on these software and hardware versions:

- Cisco Cloud Services Router running Cisco IOS® XE 16.9.2

- AnyConnect client version 4.6.03049 running on Windows 10

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, ensure that you understand the potential impact of any command.

Background Information

AnyConnect-EAP, also known as aggregate authentication, allows a Flex Server to authenticate the AnyConnect client via the Cisco proprietary AnyConnect-EAP method.

Unlike standard based Extensible Authentication Protocol (EAP) methods such as EAP-Generic Token Card (EAP-GTC), EAP- Message Digest 5 (EAP-MD5) and so on, the Flex Server does not operate in EAP pass-through mode.

All EAP communication with the client terminates on the Flex Server and the required session key used to construct the AUTH payload is computed locally by the Flex Server.

The Flex Server has to authenticate itself to the client with certificates as required by the IKEv2 RFC.

Local user authentication is now supported on the Flex Server and remote authentication is optional.

This is ideal for small scale deployments with less number of remote access users and in environments with no access to an external Authentication, Authorization, and Accounting (AAA) server.

However, for large scale deployments and in scenarios where per-user attributes are desired it is still recommended to use an external AAA sever for authentication and authorization.

The AnyConnect-EAP implementation permits the use of Radius for remote authentication, authorization and accounting.

Network Diagram

Configure

Authentication and Authorization of users with the Local Database

Note: In order to authenticate users against the local database on the router, EAP needs to be used. However, to use EAP, the local authentication method has to be rsa-sig, so the router needs a proper certificate installed on it, and it cannot be a self-signed certificate.

Sample configuration that uses local user authentication, remote user and group authorization and remote accounting.

Step 1. Enable AAA, and configure authentication, authorization and accounting lists and add a username to the local database:

aaa new-model

!

aaa authentication login a-eap-authen-local local

aaa authorization network a-eap-author-grp local

!

username test password cisco123

Step 2. Configure a trustpoint intended to hold the router certificate. PKCS12 file import is used in this example. For other options, please consult the PKI (Public Key Infrastructure) configuration guide:

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/sec_conn_pki/configuration/xe-3s/sec-pki-xe-3s-book/sec-cert-enroll-pki.html

Router(config)# crypto pki import IKEv2-TP pkcs12 bootflash:IKEv2-TP.p12 password cisco123

Step 3. Define an IP local pool to assign addresses to AnyConnect VPN clients:

ip local pool ACPOOL 192.168.10.5 192.168.10.10

Step 4. Create an IKEv2 local authorization policy:

crypto ikev2 authorization policy ikev2-auth-policy

pool ACPOOL

dns 10.0.1.1

Step 5 (Optional). Create desired IKEv2 proposal and policy. If not configured, smart defaults are used:

crypto ikev2 proposal IKEv2-prop1

encryption aes-cbc-256

integrity sha256

group 14

!

crypto ikev2 policy IKEv2-pol

proposal IKEv2-prop1

Step 6. Create AnyConnect profile

Note: The AnyConnect profile needs to be delivered to the client machine. Please refer to the next section for more information.

Configure the client profile with the AnyConnect Profile Editor as shown in the image:

Click "Add" to create an entry for the VPN gateway. Make sure to select "IPsec" as "Primary Protocol". Uncheck the "ASA gateway" option.

Save the profile: FIle -> Save As. The XML equivalent of the profile:

<?xml version="1.0" encoding="UTF-8"?>

<AnyConnectProfile xmlns="http://schemas.xmlsoap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schemas.xmlsoap/encoding/ AnyConnectProfile.xsd">

<ClientInitialization>

<UseStartBeforeLogon UserControllable="true">false</UseStartBeforeLogon>

<AutomaticCertSelection UserControllable="true">false</AutomaticCertSelection>

<ShowPreConnectMessage>false</ShowPreConnectMessage>

<CertificateStore>All</CertificateStore>

<CertificateStoreMac>All</CertificateStoreMac>

<CertificateStoreOverride>false</CertificateStoreOverride>

<ProxySettings>Native</ProxySettings>

<AllowLocalProxyConnections>true</AllowLocalProxyConnections>

<AuthenticationTimeout>12</AuthenticationTimeout>

<AutoConnectOnStart UserControllable="true">false</AutoConnectOnStart>

<MinimizeOnConnect UserControllable="true">true</MinimizeOnConnect>

<LocalLanAccess UserControllable="true">false</LocalLanAccess>

<DisableCaptivePortalDetection UserControllable="true">false</DisableCaptivePortalDetection>

<ClearSmartcardPin UserControllable="true">true</ClearSmartcardPin>

<IPProtocolSupport>IPv4,IPv6</IPProtocolSupport>

<AutoReconnect UserControllable="false">true

<AutoReconnectBehavior UserControllable="false">ReconnectAfterResume</AutoReconnectBehavior>

</AutoReconnect>

<AutoUpdate UserControllable="false">true</AutoUpdate>

<RSASecurIDIntegration UserControllable="false">Automatic</RSASecurIDIntegration>

<WindowsLogonEnforcement>SingleLocalLogon</WindowsLogonEnforcement>

<WindowsVPNEstablishment>LocalUsersOnly</WindowsVPNEstablishment>

<AutomaticVPNPolicy>false</AutomaticVPNPolicy>

<PPPExclusion UserControllable="false">Disable

<PPPExclusionServerIP UserControllable="false"></PPPExclusionServerIP>

</PPPExclusion>

<EnableScripting UserControllable="false">false</EnableScripting>

<EnableAutomaticServerSelection UserControllable="false">false

<AutoServerSelectionImprovement>20</AutoServerSelectionImprovement>

<AutoServerSelectionSuspendTime>4</AutoServerSelectionSuspendTime>

</EnableAutomaticServerSelection>

<RetainVpnOnLogoff>false

</RetainVpnOnLogoff>

<AllowManualHostInput>true</AllowManualHostInput>

</ClientInitialization>

<ServerList>

<HostEntry>

<HostName>VPN IOS-XE</HostName>

<HostAddress>vpn.example.com</HostAddress>

<PrimaryProtocol>IPsec

<StandardAuthenticationOnly>true

<AuthMethodDuringIKENegotiation>EAP-AnyConnect</AuthMethodDuringIKENegotiation>

</StandardAuthenticationOnly>

</PrimaryProtocol>

</HostEntry>

</ServerList>

</AnyConnectProfile>

Note: AnyConnect uses '*$AnyConnectClient$*' as its default IKE identity of type key-id. However, this identity can be manually changed in the AnyConnect profile to match deployment needs.

Note: In order to upload the XML profile to the router, Cisco IOS® XE 16.9.1 version or later is required. If older version of Cisco IOS® XE software is used, the profile download capability needs to be disabled on the client. Please refer to the section "Disable the AnyConnect downloader capability" for more information.

Upload the created XML profile to the flash memory of the router and define the profile:

crypto vpn anyconnect profile acvpn bootflash:/acvpn.xml

Note: The filename used for AnyConnect XML profile is acvpn.xml.

Step 7. Create an IKEv2 profile for AnyConnect-EAP method of client authentication.

crypto ikev2 profile AnyConnect-EAP

match identity remote key-id *$AnyConnectClient$*

authentication local rsa-sig

authentication remote anyconnect-eap aggregate

pki trustpoint IKEv2-TP

aaa authentication anyconnect-eap a-eap-authen-local

aaa authorization group anyconnect-eap list a-eap-author-grp ikev2-auth-policy

aaa authorization user anyconnect-eap cached

virtual-template 100

anyconnect profile acvpn

Note: For the EAP / anyconnect-eap remote authentication methods please ensure the local authentication method is configured as rsa-sig before the remote authenetication method is configured.

Step 8. Disable HTTP-URL based certificate lookup and HTTP server on the router:

no crypto ikev2 http-url cert

no ip http server

no ip http secure-server

Note: Please refer Cisco IOS and IOS-XE Next Generation Encryption Support document to confirm whether your router hardware supports the NGE algorithms (for example sha-256, aes-gcm, ecdh, ecdsa), otherwise, IPSec SA installation on the hardware fails at the last stage of tunnel establishment.

Step 9. Define the encryption and hash algorithms used to protect data

crypto ipsec transform-set TS esp-aes 256 esp-sha256-hmac

mode tunnel

Step 10. Create an IPSec profile:

crypto ipsec profile AnyConnect-EAP

set transform-set TS

set ikev2-profile AnyConnect-EAP

Step 11. Configure a loopback interface with some dummy IP address. The Virtual-Access interfaces borrow the IP address from it.

interface loopback100

ip address 10.0.0.1 255.255.255.255

Step 12. Configure a virtual-template (associate the template in the IKEv2 profile)

interface Virtual-Template100 type tunnel

ip unnumbered Loopback100

ip mtu 1400

tunnel mode ipsec ipv4

tunnel protection ipsec profile AnyConnect-EAP

Steap 13 (Optional). By default, all traffic from the client is sent through the tunnel. You can configure split tunnel, which allows only selected traffic to go through the tunnel.

ip access-list standard split_tunnel

permit 10.0.0.0 0.255.255.255

!

crypto ikev2 authorization policy ikev2-auth-policy

route set access-list split_tunnel

Step 14 (Optional). If all traffic is required to go through the tunnel, configure NAT in order to allow internet connectivity for remote clients.

ip access-list extended NAT

permit ip 192.168.10.0 0.0.0.255 any

!

ip nat inside source list NAT interface GigabitEthernet1 overload

!

interface GigabitEthernet1

ip nat outside

!

interface Virtual-Template 100

ip nat inside

Example: AnyConnect Profile Download Configuration

This example shows how to configure the FlexVPN AnyConnect Profile Download feature:

Note: You do not modify the Local Policy files on the Anyconnect Client machine. After the configuration of Anyconnect Profile Download feature on IKEv2, the required XML profiles get automatically downloaded on the client device.

Note: You must not use the HTTPS server and SSL policy together. Before SSL policy is enabled please disable ip http secure-server. If both these features are enabled at the same time and the device receives an incoming SSL VPN connection, the device can crash.

no ip http secure-server

crypto ssl policy ssl-policy

pki trustpoint IKEv2-TP sign

ip address local 10.0.0.1 port 443

no shutdown

crypto ssl profile ssl_prof

match policy ssl-policy

Disable the AnyConnect downloader capability (optional).

This step is only necessary if Cisco IOS® XE software version older than 16.9.1 is used. Prior to Cisco IOS® XE 16.9.1 the capability to upload the XML profile to the router was not available. The AnyConnect client tries to perform download of the XML profile after successful login by default. If the profile is not available, the connection fails. As a workaround, it is possible to disable the AnyConnect profile download capability on the client itself. In order to do that, this file can be modified:

For Windows:

C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\AnyConnectLocalPolicy.xml

For MAC OS:

/opt/cisco/anyconnect/AnyConnectLocalPolicy.xml

The "BypassDownloader" option is set to "true", for example:

<?xml version="1.0" encoding="UTF-8"?>

<AnyConnectLocalPolicy xmlns="http://schemas.xmlsoap/encoding/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://schemas.xmlsoap/encoding/ AnyConnectLocalPolicy.xsd" acversion="4.6.03049">

<BypassDownloader>true</BypassDownloader>

<EnableCRLCheck>false</EnableCRLCheck>

<ExcludeFirefoxNSSCertStore>false</ExcludeFirefoxNSSCertStore>

<ExcludeMacNativeCertStore>false</ExcludeMacNativeCertStore>

<ExcludePemFileCertStore>false</ExcludePemFileCertStore>

<ExcludeWinNativeCertStore>false</ExcludeWinNativeCertStore>

<FipsMode>false</FipsMode>

<RestrictPreferenceCaching>false</RestrictPreferenceCaching>

<RestrictTunnelProtocols>false</RestrictTunnelProtocols>

<RestrictWebLaunch>false</RestrictWebLaunch>

<StrictCertificateTrust>false</StrictCertificateTrust>

<UpdatePolicy>

<AllowComplianceModuleUpdatesFromAnyServer>true</AllowComplianceModuleUpdatesFromAnyServer>

<AllowISEProfileUpdatesFromAnyServer>true</AllowISEProfileUpdatesFromAnyServer>

<AllowServiceProfileUpdatesFromAnyServer>true</AllowServiceProfileUpdatesFromAnyServer>

<AllowSoftwareUpdatesFromAnyServer>true</AllowSoftwareUpdatesFromAnyServer>

<AllowVPNProfileUpdatesFromAnyServer>true</AllowVPNProfileUpdatesFromAnyServer></UpdatePolicy>

</AnyConnectLocalPolicy>

After the modification, the AnyConnect client needs to be restarted.

AnyConnect XML profile delivery

With the fresh installation of the AnyConnect (with no XML profiles added), the user is able to manually enter the FQDN of the VPN gateway in the address bar of AnyConnect client. This results in the SSL connection to the gateway. The AnyConnect client does not attempt to establish the VPN tunnel with IKEv2/IPsec protocols by default. This is the reason that the XML profile is installed on the client is mandatory to establish the IKEv2/IPsec tunnel with Cisco IOS® XE VPN gateway.

The profile is used when it is selected from the drop-down list of AnyConnect address bar.

The name that appears is the same name as specified in "Display Name" in AnyConnect profile editor.

The XML profile can be manually put into this directory:

For Windows:

C:\ProgramData\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

For MAC OS:

/opt/cisco/anyconnect/profile

The AnyConnect client needs to be restarted in order for the profile to become visible in the GUI. It is not sufficient to close the AnyConnect window. The process can be restarted by right-clicking AnyConnect icon in the Windows tray and select "Quit" option:

Communication flow

IKEv2 and EAP exchange

Verify

Use this section in order to confirm that your configuration works properly.

! Check IKEv2 SA parameters

Router# show crypto ikev2 sa detailed

IPv4 Crypto IKEv2  SA

Tunnel-id Local                 Remote                fvrf/ivrf            Status

1         192.0.2.1/4500     192.0.2.100/50899    none/none            READY

Encr: AES-CBC, keysize: 256, PRF: SHA256, Hash: SHA256, DH Grp:14, Auth sign: RSA, Auth verify: AnyConnect-EAP

Life/Active Time: 86400/758 sec

CE id: 1004, Session-id: 4

Status Description: Negotiation done

Local spi: 413112E83D493428       Remote spi: 696FA78292A21EA5

Local id: 192.0.2.1

Remote id: *$AnyConnectClient$*

Remote EAP id: test        <------ username

Local req msg id:  0              Remote req msg id:  31

Local next msg id: 0              Remote next msg id: 31

Local req queued:  0              Remote req queued:  31

Local window:      5              Remote window:      1

DPD configured for 0 seconds, retry 0

Fragmentation not  configured.

Dynamic Route Update: disabled

Extended Authentication not configured.

NAT-T is detected  outside

Cisco Trust Security SGT is disabled

Assigned host addr: 192.168.10.8.  <---- Assigned IP

Initiator of SA : No

! Check the crypto session information

Router# show crypto session detail

Crypto session current status

Code: C - IKE Configuration mode, D - Dead Peer Detection

K - Keepalives, N - NAT-traversal, T - cTCP encapsulation

X - IKE Extended Authentication, F - IKE Fragmentation

R - IKE Auto Reconnect, U - IKE Dynamic Route Update

S - SIP VPN

Interface: Virtual-Access1. <----- Virtual interface associated with the client

Profile: AnyConnect-EAP

Uptime: 00:14:54

Session status: UP-ACTIVE

Peer: 192.0.2.100 port 50899 fvrf: (none) ivrf: (none). <----- Public IP of the remote client

Phase1_id: *$AnyConnectClient$*

Desc: (none)

Session ID: 8

IKEv2 SA: local 192.0.2.1/4500 remote 192.0.2.100/50899 Active

Capabilities:N connid:1 lifetime:23:45:06

IPSEC FLOW: permit ip 0.0.0.0/0.0.0.0 host 192.168.10.8

Active SAs: 2, origin: crypto map

Inbound:  #pkts dec'ed 89 drop 0 life (KB/Sec) 4607990/2705. <------ Packets received from the client

Outbound: #pkts enc'ed 2 drop 0 life (KB/Sec) 4607999/2705. <------ Packets sent to the client

! Check the actual configuration applied for the Virtual-Acces interface associated with client

Router# show derived-config interface virtual-access 1.

Building configuration...

Derived configuration : 258 bytes

!

interface Virtual-Access1

ip unnumbered Loopback100

ip mtu 1400

ip nat inside

tunnel source 192.0.2.1

tunnel mode ipsec ipv4

tunnel destination 192.0.2.100

tunnel protection ipsec profile AnyConnect-EAP

no tunnel protection ipsec initiate

end

Troubleshoot

This section provides information you can use in order  to troubleshoot your configuration.

1. IKEv2 debugs to collect from the headend:

debug crypto ikev2

debug crypto ikev2 packet

debug crypto ikev2 error

2. AAA debugs to see assignment of local and/or remote attributes:

debug aaa authorization

debug aaa authentication

3. DART from the AnyConnect client.