On Wed, May 26, 2010 at 11:17 AM, Mike Walter <mwal...@3z.net> wrote: > We have been struggling to locate someone at AT&T that handles the > txt.att.net servers. We have clients in our data center that can no > longer send emails to mobile phones via 10di...@txt.att.net. We have > contacted AT&T and they say there is no problem on their end. We can > ping the server, but simply cannot connect to port 25. We have checked > all firewalls of each client. Some ranges of IPs work and others don't. > Looking for someone with a clue who can assist.
this is not a guaranteed service, nor does it have an official SLA, and inbound mail/connections from louder speakers are often just dropped, either at the TCP layer, or at the application layer (even after what seems like a completed SMTP conversation.) If you depend upon SMS for things, smtp -> sms gateways at the provider aren't reliable enough.