txt.att.net operators

[morrowc.lists at gmail.com (Christopher Morrow)]

On Wed, May 26, 2010 at 11:17 AM, Mike Walter <mwalter at 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 10digit at 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.