[Openswan Users] VPN Client thru Alcatel Modem

Robert W. Burgholzer rburgholzer at maptech-inc.com
Wed May 19 12:00:09 CEST 2004

What kind of client is behind the Alcatel modem?


At 04:30 PM 5/19/2004 +0200, Leonard Tulipan wrote:
>After a lot of debugging, I am finally stranded.
>We have the followin setup
> VPN Client
>Alcatel DSL Router Speedtouch 510
>Changing IP's
>X.X.X.X Linux VPN Firewall
>192.168.118.* Private Net behind FW
>Ok, nothing interesting.
>Now, when I trace VPN Connections with tcpdump, I see
>client:UDPPort500 -> server:Port500 ISAKMP Phase 1, 2, etc
>So Packets ALWAYS come from Port 500 and go to Port 500
>I also checked the VPN client it also behaves well and has Port 500 as 
>But the Alcatel Router (after getting the firewall-config to let the 
>corresponding traffic thru) changes all that, so that I get packets 
>looking like
>dslrouter:UDPPort(Random between 19000 and 20000) -> server:Port500
>This does not work!
>Is THIS the one reason I need the NAT-T Patch, or can I somehow get the 
>server to accept packages, even though, the src_port isn't correct?
>Users mailing list
>Users at lists.openswan.org

Robert Burgholzer
Environmental Engineer
MapTech Inc.

More information about the Users mailing list