Hey folks, Someone forwarded this directly to my inbox, much appreciated. We’ll work with Martin to get this sorted out. -- Alex Brotman Sr. Engineer, Anti-Abuse & Messaging Policy Comcast From: NANOG <nanog-bounces+alex_brotman=comcast.com@nanog.org> On Behalf Of Martin Cook Sent: Friday, June 7, 2024 2:15 PM To: nanog@nanog.org Subject: Comcast.net email servers - temporarily blacklisted IP Address errors Hello NANOG, We recently started getting some complaints from customers experiencing an error when trying to access their old Comcast.net email accounts with one of their email clients (outlook tbird etc.) via POP3 or IMAP. Web based use of their email via the Comcast portal is unaffected. "ERR [AUTH] Temporarily blacklisted IP Address - try again later" These customers are previous Residential HSI subscribers of Comcast who have since moved to other internet service providers, including ours, and are still allowed to use their old email accounts. There is a web portal based method for attempting to get individual IP addresses removed from the "temporary black list". But due to the number of reports we have had in a very short period of time we believe an entire range of IP's (possibly a /17) has been blacklisted as of last Friday-ish We're having difficulty resolving this issue through Comcast customer support or the Comcast Security assurance team. So I'm looking to see if anyone from Comcast or someone who has had this issue before reach out off-list to assist with resolving this headache. **** Enjoy N91 next week for all the people attending, stop by to attend Jason Rokeach's talk on "meshrr: Hierarchical Route Distribution @ Scale w/ Kubernetes on Wednesday!" I'm sure he will have some awesome things to show everyone. Thanks, Martin Cook