[imp] IMP compose vs transparent proxy

[Syahrul Sazli Shaharir]

Hi,

I maintain an IMP RELENG_3 installation, with php-4.2.3, apache 1.3.26.
Users from one ISP complains that the compose window fails on 'Send
Message' button (hangs indefinitely while connecting to the server).

tcpdump on the server reveals nothing -- the submit action never reaches
the server. The only clue is, from the HTTP headers prior to that, the ISP
uses Netapp NetCache transparent proxy:-

Via: 1.1 NetCache01 (NetCache NetApp/5.3.1R2)

I suspect the request gets stuck in the proxy and never arrives to IMP.
What are the possibilities of the cause of this problem?

Thanks in advance..

--sazli
cd /open/source; make world
http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x06D4113E
Key fingerprint = 0776 CC02 2C3F C0FF 7312  0C3E 0593 AF64 06D4 113E