Yep... SNPP or WCTP are typically what is used for the "enterprise messaging" product that the carriers offer. Most of them require either authentication, or providing a list of authorized destination numbers in advance to cut down on abuse. ________________________________ From: NANOG <nanog-bounces+tim=mid.net@nanog.org> on behalf of Aaron de Bruyn via NANOG <nanog@nanog.org> Sent: Friday, January 20, 2023 8:28:39 AM To: dwalters@omnigo.com; William Herrin Cc: NANOG mailing list Subject: Re: txt.att.net outage? I guess SNPP is still a thing: $ host snpp.att.net<http://snpp.att.net> snpp.att.net<http://snpp.att.net> is an alias for snpp.att.unimobile.com<http://snpp.att.unimobile.com>. snpp.att.unimobile.com<http://snpp.att.unimobile.com> is an alias for snpp-att.gmes.syniverse.com<http://snpp-att.gmes.syniverse.com>. snpp-att.gmes.syniverse.com<http://snpp-att.gmes.syniverse.com> has address 173.209.208.78 $ telnet 173.209.208.78 444 Trying 173.209.208.78... Connected to 173.209.208.78. Escape character is '^]'. 220 SNPP Gateway Ready ^] telnet> quit Connection closed. $ -A On Fri Jan 20, 2023, 02:24 PM GMT, Aaron de Bruyn<mailto:aaron@heyaaron.com> wrote: txt.att.net<http://txt.att.net> is returning MX records and those machines don't have port 444 open... Wouldn't you want to be sending something like a SNPP message instead? It's a much less convoluted delivery process and is almost real-time (no queuing). I guess it's been a decade or so since I've dealt with emergency services and paging...is SNPP even a thing anymore? I looked at some old code I wrote (https://github.com/darkpixel/snppsend/blob/master/more-providers), and it doesn't look like snpp.attws.net<http://snpp.attws.net> exists. -A On Fri Jan 20, 2023, 02:12 PM GMT, William Herrin<mailto:bill@herrin.us> wrote: On Thu, Jan 19, 2023 at 8:09 PM Dan Walters via NANOG <nanog@nanog.org> wrote: Know this is a longshot, any chance anyone from the txt.att.net domain might be able to help us with what we believe is a blacklist block or possibly an outage? We deal with 911 cad dispatching and is affecting first responders so looking to see if there is a faster way to resolution. Hi Dan, As I understand it, txt.att.net is a low-volume courtesy service not intended for important communications. A paid service like Twilio can handle production-grade SMS delivery. Regards, Bill Herrin -- For hire. https://bill.herrin.us/resume/