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ASA5540 as a remote VPN server, OpenBSD as a client

SuperVitya
Level 1
Level 1

Hello, collegues!

There is a VPN scheme where two sites are connected with a VPN tunnel. Both peers are based on OpenBSD. The remote site does not have a static IP address so the standard site-to-site VPN is not possible. This peer is configured as a remote VPN client. Here is its configuration in ipsec.conf file:

ike dynamic esp from 172.27.77.0/24 to { 192.168.254.0/24 192.168.200.0/24 192.168.252.0/24 } \
    peer x.x.x.x \
    aggressive auth hmac-sha1 enc 3des \
    quick auth hmac-sha1 enc aes-128 \
    srcid "username@domain" psk "<pre-shared-key>"

On the server I found the isakmpd.conf file with parameters for all VPNs terminated on the device. Specifically for this peer the following string is:

[username@domain]

Authentication=                 <pre-shared-key>

As we see there is not as many parameters as we use on Cisco VPN Client. No tunnel-group and no pre-shared key. (I think the mentioned 'pre-shared-key' is used in x-auth mode authentication).

And now I need to replace the local OpenBSD server with ASA5540 and to configure as a Remote Access VPN server for the peer.

If anybody has dealt with this kind of communication before, please, help me configure ASA5540 for this.

Thank you.

1 Reply 1

Marcin Latosiewicz
Cisco Employee
Cisco Employee

Viktor,

Has anyone looked into this already?

Looks like you're doing aggrssive mode and no xauth on the BSD system.

I'm not sure about openbsd but maybe:

username@domain is your ID

and psk is the pass - that's what it would look like to me.

On ASA you can disable xauth for particular tunnel group:

tunnel-group username@domain type remote-access
tunnel-group username@domain ipsec-attributes
  pre-shared-key psk
isakmp ikev1-user-authentication none

I don't know how openbsd implements it and used this as reference:

srcid string dstid string
Define the unique ID that isakmpd(8) will use as the identity of the local (srcid) and remote (dstid) peer; if omitted, the IP address is used.


http://www.kernel-panic.it/openbsd/vpn/vpn3.html


Marcin