On 2016-02-03 18:14, Guillaume Nault wrote:
On Wed, Feb 03, 2016 at 11:04:31AM +1100, Stephen Hemminger wrote:
Please excuse URL mangling, my bugzilla address appears to route through
stupid corporate firewall.
Sorin, it seems like one of your L2TP tunnels is routed to one of its upper PPP
devices. Most likely, the peer address of the PPP device is also the address of
the remote L2TP tunnel endpoint. So L2TP packets are sent back to the upper PPP
device, instead of leaving through the physical interface.
Thank you. You are right. There's a host route to the peer over the ppp0
interface in the routing table. I don't know how it gets there. I've
checked the source code of pppd and no such route is added for kernels
newer than 2.1.16. I've grepped /etc for "route" in order to detect a
"post-up" script that would add that route. Nothing. I've double-checked
by executing strace on xl2tpd and its children (i.e. pppd and the
initialisation scripts) and I couldn't find any ioctl SIOCADDRT. So it's
a total mystery for me where that route comes from. Could it come from
the kernel?
I've found this 9-year-old bug report:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=444180. I've adopted
the strategy that the comment proposes: delete the route in an post-up
script.
Thanks again.
Best regards,
Sorin
