possible firewall filtering issues (port 9279 not blocked though)

["N.J. Thomas" <njt@ayvali.org>]

I'm attempting to run tarsnap on a machine behind a perimeter firewall,
but there's none on the box itself.

AFAIK, the firewall is not filtering port 9279.

However, any tarsnap operation I run hangs indefinitely, and eventually
dies.

Running tcpdump/wireshark and sniffing the connection shows that there
is definitely communication going on between my box and the tarsnap
server (on Amazon), however at some point, the tarsnap server refuses to
continue speaking to my box, and then hangs.

Anyone seen anything similar before?

I suspect my firewall may be to blame, but I'm not sure exactly what is
going on.

fwiw: I'm running tarsnap-1.0.33 built from ports on a FreeBSD
9.1-RELEASE box (amd64). My account is used successfully on a separate
machine (with another key), so I know that works, I generated a new key
for this particular box.

cperciva: I can send you the tcpdump capture file output if you like.

Thomas