In article <20060429042321.GA19658@azeotrope.org>,  <khym@azeotrope.org> wrote:
>I have a NetBSD/i386 machine running a kernel from late November 2005
>(version 3.99.11) as one end of an IPsec tunnel (the other end is Linux,
>but I don't think that matters). It works great except for one thing...
>it doesn't seem to pass large packets. ping -s 1418 works, but
>ping -s 1419 doesn't.. If I run tcpdump on the NetBSD
>end of the tunnel endpoint and watch the unencrypted side when I do a
>ping -s 1419, I see:
>
>23:17:13.218441 IP 10.1.1.73 > 10.2.1.20: icmp 1427: echo request seq 0
>23:17:14.220058 IP 10.1.1.73 > 10.2.1.20: icmp 1427: echo request seq 1
>23:17:15.220100 IP 10.1.1.73 > 10.2.1.20: icmp 1427: echo request seq 2
>23:17:16.220159 IP 10.1.1.73 > 10.2.1.20: icmp 1427: echo request seq 3
>
>However, if I watch the external interface, I don't see any ESP packets
>at all. If I repeat the same thing with ping -s 1418, I get the expected
>result: echo requests get encrypted, and I see the ESP packets go out.
>
>Anyone know what the problem might be?

What is net.inet.ipsec.dfbit? If it is not 2, try 2.

christos