From: "Paul Smedley" <ecs-isp@2rosenthals.com>
Message-ID: <c43ab253-3163-4a18-84a1-b70415c96d43@smedley.id.au>
Date: Fri, 21 Feb 2025 07:26:41 +1030
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Subject: Re: [eCS-ISP] Anyone else seeing issues today with AT&T and RDNS
 failures when sending?
To: eCS ISP Mailing List <ecs-isp@2rosenthals.com>
References: <list-12280221@2rosenthals.com>
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Hey Lewis,

On 21/2/25 07:05, Lewis G Rosenthal wrote:
> 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:
>
>   <recipient-address @ att.net>
>     host ff-ip4-mx-vip1.prodigy.net [144.160.159.21]
>     SMTP error from remote mail server after MAIL FROM:<sender from 
> the 2rosenthals.com domain>:
>     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.
>
Confirmed also that rdns works for your IP from the other side of the 
planet..

psmedley@ThinkPad-X13-Gen-1:~$ host 50.73.8.217
217.8.73.50.in-addr.arpa domain name pointer secmgr-va.2rosenthals.com.

Cheers,

Paul