From: "Lewis G Rosenthal" Received: from [50.73.8.217] (account lgrosenthal@2rosenthals.com HELO [192.168.200.27]) by 2rosenthals.com (CommuniGate Pro SMTP 5.4.10) with ESMTPSA id 12280220 for ecs-isp@2rosenthals.com; Thu, 20 Feb 2025 15:35:30 -0500 To: eCS-ISP Subject: Anyone else seeing issues today with AT&T and RDNS failures when sending? Organization: Rosenthal & Rosenthal, LLC Message-ID: <67B7920D.3090509@2rosenthals.com> Date: Thu, 20 Feb 2025 15:35:25 -0500 User-Agent: Mozilla/5.0 (OS/2; Warp 4.5; rv:38.0) Gecko/20100101 Firefox/38.0 SeaMonkey/2.35 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi, all... It's rare that I get an RDNS failure for one of my server IPs, as I know I have (and have just confirmed again) valid RDNS records in my providers' DNS. Today, att.net rejected mail from us to one of their subscribers with a 550 5.7.1 error: host ff-ip4-mx-vip1.prodigy.net [144.160.159.21] SMTP error from remote mail server after MAIL FROM:: 550 5.7.1 Connections not accepted from servers without a valid sender domain.flph829 Fix reverse DNS for 50.73.8.217 50.73.8.217 is our Leesburg, VA public IP on Comcast's network (I know; I'm so ashamed...we're in the only four square blocks in downtown Leesburg where Verizon FiOS is *still* not available). The RDNS record is: secmgr-va.2rosenthals.com (verified a few minutes ago at MX-Toolbox) I'm wondering if anyone else is having difficulty today. TIA -- Lewis ------------------------------------------------------------- Lewis G Rosenthal, CNA, CLP, CLE, CWTS, EA Rosenthal & Rosenthal, LLC www.2rosenthals.com visit my IT blog www.2rosenthals.net/wordpress -------------------------------------------------------------