On Oct 31, 2007 12:24 AM, Shawn Everett <shawn at tandac.com> wrote: > > telnet smtp.isp.net 25 generates the following: > Trying a.b.c.d... > Connected to smtp.isp.net. > Escape character is '^]'. > > And then nothing. All other machines can connect to smtp.isp.net 25 > without a problem. They also use that host for their outgong mail server. Have you contacted "isp.net", whoever they are, to make sure that they have not blackholed or tarpitted that particular machine's IP address for some reason?