Mailing List Archive

GRE Tunnel problems, slightly off-topic
Hi folks,

I am extensively testing GRE compatibility between Linux (iptunnel
a.k.a. ip tunnel), FreeBSD (gre-tun) and OpenBSD (ifconfig gre0 tunnel
...). While the IP-IP stuff workes nicely so far and I consider my
configs correct and messed quite some time with sniffers
(self-confidence, I know :-)) Before flooding with configs I'd like to
request feedback on your GRE setups. Have you encountered any
incompatibility with Cisco encapsulation?

Question: When routing a prefix into a tunnel, would you rather use the
near or far end of the /30 link as gateway, "it depends" I guess? Linux
is capable of routing towards dev gre0, on the other OSs I guess one has
to rely on the attached pseudo-interface addresses.

Did you get any of the following combinations work:

OpenBSD <--> Cisco gre ip tunnel
Linux <--> FreeBSD

Linux --> Cisco only works in one direction (echo request, echo reply),
I have no clue why.

Muchas gracias,

Dipl.-Ing. Gernot W. Schmied, MS Network Architecture & Operations
Senior Strategist Research Group
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