Timothy Taylor wrote:
> That almost sounds like the isp has a transparent proxy in the way. Do
> you have multiple public IP addresses? Can you check from one of them?
> If you turn on logging for the smtp rule, or traffic capture on the mail
> host, what do you see? Does the same problem occur with the old software
> on the new IP address?

Hi,
I have another machine that is outside of the fw, but inside the range
controlled by the ISP, and from there everything works fine. I'll
investigate if the ISP has some gadget on port 25 (it is the same ISP I
had on the old network, where this problem does not exist).

Thanks for the quick answer: I know where to look now.

Cheers, Giuseppe