Hi Jason,
At 16:55 11.05.2005, you wrote:
looks like the port 25 packet is getting dropped by something between your test machine and host X. either the ISP of client machine or your ISP filters TCP port 25 traffic (not uncommon).
I have now tested it from different machines (with different ISPs). In fact, that's the reason. The ISP of the host X has dropped the packets over port 25.
Many thanks for help!
Ludger