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Date:      Wed, 5 Feb 2014 17:08:24 -0700
From:      John Nielsen <lists@jnielsen.net>
To:        "freebsd-stable@freebsd.org Stable" <freebsd-stable@freebsd.org>
Cc:        freebsd-ipfw@freebsd.org
Subject:   IPFW fwd not working after upgrade from 9.2 to 10.0
Message-ID:  <8C9CDEF4-A44A-4207-BB87-DA3E7CF89917@jnielsen.net>

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I have been using IPFW FWD to do per-interface routing on a VM instance. =
The default gateway is on interface vtnet0, but there is a second =
interface, vtnet1, on a different network with its own public IP =
address. The second network has its own gateway, which I'd like to use =
for responses to connections coming on on vtnet1. Under 9.2, the below =
worked fine:

fwd ${GW2} ip from ${PUBIP2} to not table(120) out via vtnet0

Table 120 contains all the local networks for which I don't want the =
rule to apply.

I updated the VM to 10.0-RELEASE, with no changes to the IPFW rules or =
network configuration. The forwarding to the secondary router no longer =
works. Traffic comes in on ${PUBIP2} fine, and the counter for the IPFW =
rule increments, but no packets are actually sent out vtnet1. Instead, =
it's trying to do a weird ARP query:


# tcpdump -n -p -i vtnet1
...
16:46:33.146324 IP ${OUTSIDE_IP}.55063 > ${PUBIP2}.22: Flags [S], seq =
2242981455, win 65535, options [mss 1460,nop,wscale 4,nop,nop,TS val =
1978614336 ecr 0,sackOK,eol], length 0
16:46:33.146372 ARP, Request who-has ${GW1} tell ${PUBIP2}, length 28

If I try to SSH from an outside IP to the public IP on vtnet1, a =
response never goes out either interface (vtnet0 or vtnet1). Instead, an =
ARP query is going out (on vtnet1) looking for the default gateway IP, =
which is only reachable on vtnet0.

On the off chance this is not a bug, is there a better way I should be =
doing per-interface routing under FreeBSD 10? If it is a bug, can anyone =
suggest what might be going on here and how to track it down further?

Thanks,

JN




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