On Tue, 15 Nov 2011, Yoav Nir wrote:

FreeS/WAN did eliminate transport mode, but that project is dead. The project 
that is active now (strongSwan) does have it.

<openswan hat>

So does openswan, which is the continuation project from FreeS/WAN, and had its 
most recent software
release just a few weeks ago. But we wish people would not use either transport 
mode or AH.

RFC 3191 (L2TP over IPsec) says that transport mode MUST be supported for L2TP 
over IPsec. That, and the fact that this is the way Microsoft implemented their 
L2TP client is the reason why most gateway vendors have implemented transport 
mode. That and the fact that Cisco like to encrypt their GRE tunnels in 
transport mode.

openswan also supports multiple L2TP clients behind the same NAT router
and multiple L2TP clients on the same overlapping pre-NAT IP address
using the KLIPS stack with SAref tracking using two new socket options and
ip_conntrack. The NETKEY builtin stack for Linux has no such capability.

See:

http://www.openswan.org/docs/ipsecsaref.png
https://gsoc.xelerance.com/projects/openswan/wiki/L2TPIPsec_configuration_using_openswan_and_xl2tpd
https://gsoc.xelerance.com/projects/openswan/wiki/Building_and_Installing_an_SAref_capable_KLIPS_version_for_DebianUbuntu

The same funcionality is used with Openswan to support multiple connections 
with customers with
unknown RFC1918 address space that overlaps, which is common in large cloud 
deployments.

Paul
_______________________________________________
IPsec mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/ipsec

Reply via email to