Howdy, I’ve remediated this, but hasn’t been deployed yet. Should be later today.
As always, folks looking for help with comcast.net can use [email protected]<mailto:[email protected]> -- Alex Brotman Sr. Engineer, Anti-Abuse & Messaging Policy Comcast From: Manu Sharma <[email protected]> Sent: Wednesday, November 4, 2026 2:40 AM To: [email protected] Subject: [EXTERNAL] [mailop] Looking for postmaster/deliverability contact at Comcast (comcast.net) Hi all, Does anyone have a good postmaster or deliverability contact at Comcast for comcast. net? We’re an ESP (Leadhub) investigating a delivery issue on one of our sending ranges. Since at least early September, every connection from 167. 99. 253. 0/24 Hi all, Does anyone have a good postmaster or deliverability contact at Comcast for comcast.net<https://urldefense.com/v3/__http:/comcast.net__;!!CQl3mcHX2A!Gsv4HT22YolpcMZ_z7D8Bk7U_My4pixJ1nqsapWu7FWEMr59iHmXBsrACV1jx2LbYMj4--HxdEqOcsprLwo$>? We’re an ESP (Leadhub) investigating a delivery issue on one of our sending ranges. Since at least early September, every connection from 167.99.253.0/24<https://urldefense.com/v3/__http:/167.99.253.0/24__;!!CQl3mcHX2A!Gsv4HT22YolpcMZ_z7D8Bk7U_My4pixJ1nqsapWu7FWEMr59iHmXBsrACV1jx2LbYMj4--HxdEqO6gsdsNA$> to the comcast.net<https://urldefense.com/v3/__http:/comcast.net__;!!CQl3mcHX2A!Gsv4HT22YolpcMZ_z7D8Bk7U_My4pixJ1nqsapWu7FWEMr59iHmXBsrACV1jx2LbYMj4--HxdEqOcsprLwo$> MX hosts is dropped before the SMTP greeting: lost connection with mx1a1.comcast.net<https://urldefense.com/v3/__http:/mx1a1.comcast.net__;!!CQl3mcHX2A!Gsv4HT22YolpcMZ_z7D8Bk7U_My4pixJ1nqsapWu7FWEMr59iHmXBsrACV1jx2LbYMj4--HxdEqO2jkamfE$>[96.103.145.163] while receiving the initial server greeting There’s no 5xx and no bounce text, so we can’t tell which policy we’re hitting. Mail from our other ranges is accepted by Comcast as usual. The affected IPs have matching forward and reverse DNS, and SPF/DKIM/DMARC are in place. We’ve tried the published routes without a response, so I’d like to ask whether anyone here has a contact on the team that handles inbound filtering or sender reputation. If so, I’d appreciate an introduction or contact information off-list. Thanks, Manu Leadhub
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