While working on ng_nat + libalias in kernel, I've found that sometimes in very rare conditions libalias produces completely broken packets. Fortunately they also have incorrect TCP checksum, and thus are discarded and being restransmitted. Fortunately retransmits are not broken. This is not related to any protocol aliasing, it is a bug in alias.c. I have two cases which are 100% reproducible.
The first case is an ssh session to my mailbox, I can't give reproduce recipe, sorry :) The second case is the following: you must be behind a box running natd(8) and have MTU of 1500, router running natd should have 1500 MTU on both interfaces. Now, you should run # tcpdump -w qqq -s 1600 -vvnpi fxp0 host www.rambler.ru & # fetch -vvv http:/www.rambler.ru # fg # ^C # tcpdump -s 1600 -vXXnpr qqq | less Look into incoming TCP segment with offset 2921:4381(1460). The first packet is broken one. Search again for 2921:4381(1460). Now I've found the retransmitted packet. -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
