This week I set up a new mail server on a static IP business account with ISP Spectrum. It is running Slackware 14.2 and sendmail 8.15.2.
As of yesterday, I believe I've completed all the settings required. The domain is novatec-inc.com, IP: 24.142.169.12.
When I send mail from this server to recipients at gmail.com -- and a few others, probably serviced by Google -- the messages get rejected:
Code:
The original message was received at Thu, 15 Sep 2022 23:08:15 -0400
from localhost [127.0.0.1]
----- The following addresses had permanent fatal errors -----
<user@gmail.com>
(reason: 550-5.7.1 [2603:6011:2d02:ee82:f66d:4ff:fe5f:ffd1 12] Our system has)
----- Transcript of session follows -----
... while talking to gmail-smtp-in.l.google.com.:
>>> DATA
<<< 550-5.7.1 [2603:6011:2d02:ee82:f66d:4ff:fe5f:ffd1 12] Our system has
<<< 550-5.7.1 detected that this message is likely unsolicited mail. To reduce the
<<< 550-5.7.1 amount of spam sent to Gmail, this message has been blocked. Please
<<< 550-5.7.1 visit
<<< 550-5.7.1 https://support.google.com/mail/?p=UnsolicitedMessageError
<<< 550 5.7.1 for more information. bl21-20020a05620a1a9500b006bbfaddee08si4336792qkb.70 - gsmtp
554 5.0.0 Service unavailable
I believe I have correctly set up the rDNS, DKIM and SPF records for this domain. It is not listed on any blacklist site. Diagnostic site
https://www.appmaildev.com/en/dkim show SPF and DKIM as "Pass" and rDNS exists -- not listed on any RBLs. Everything appears to be in order.
One odd bit about the message is the IPv6 address listed in the error: 2603:6011:2d02:ee82:f66d:4ff:fe5f:ffd1. When I've seen this message in the past it's had the IPv4 address. For example:
Code:
<user@safe-white.com>
(reason: 550-5.7.1 [24.142.169.10 12] Our system has detected that this message is)
----- Transcript of session follows -----
... while talking to aspmx.l.google.com.:
>>> DATA
<<< 550-5.7.1 [24.142.169.10 12] Our system has detected that this message is
<<< 550-5.7.1 likely unsolicited mail.
Has anyone run into this problem before? What can be done about it? Currently I can send messages to everyone except recipients at Google servers.
