The problem appears to be a bug in the kernel. One thing I'd forgotten to mention was that I regularly use VLAN interfaces on all of my machines. The public exit interface on the CentOS boxes was a VLAN tagged interface (eth0.2). But when I did later tests on the Fedora boxes, I just did a test on their native interfaces, which worked. At first I thought perhaps I was running into an MTU problem, but then I realized I was only sending small ICMP packets to test. And tcpdump isn't seeing any packets exit so I *think* Linux is choking on the double tagging. If I exchange the addresses, moving the public address to the untagged interface (eth0) and the private address to the tagged interface (eth0.2 for example), GRE works fine since the default route is using the publicly addressed interface and is much happier when it's untagged. Is this a bug or are 802.1q and GRE tagging just inherently incompatible? Greg _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
