[Mailman-Users] Re: "host not found" or "account .. does not exist" when host or account does exist

[Mark Sapiro]

On 3/31/21 1:07 PM, Jon Baron wrote:
> I run a mailing list with 4000 subscribers (jdm-soci...@sjdm.org). Every
> time it sends mail to the list I get about 10 failure messages (completely
> failure, not temporary failure that keeps mail in the queue) saying that
> the host is not found or the email address doesn't exist. I can often find
> the host with the (linux) "host" command, and the email address checker
> often shows that the address is valid. The same email address that failed
> usually succeeds on the next post.
> 
> I would like to keep these messages in the queue if possible, or maybe
> allow more time for finding the host, or something, before giving up on the
> first try. I cannot find a configuration option.


This is not a Mailman issue. It is between your outgoing MTA and the
recipient domain's MX MTA. If there is a solution, it will be in your
MTA. I do note that Postfix smtp at least considers "Host or domain name
not found." to be a retryable error, however if
smtpd_recipient_restrictions includes reject_unknown_recipient_domain
(which is definitely recommended against for Mailman) the mail will be
rejected by Postfix during delivery from Mailman to Postfix.

As an example, this list's server (mail.python.org) defines a separate
port in master.cf for Mailman to use with these settings:

127.0.0.1:8027
  inet  n   -   -   --  smtpd
-o smtpd_authorized_xforward_hosts=127.0.0.0/8
-o mynetworks=127.0.0.0/8
-o smtpd_recipient_restrictions=permit_mynetworks,reject
-o smtpd_client_restrictions=
-o smtpd_helo_restrictions=
-o smtpd_sender_restrictions=
-o smtpd_data_restrictions=
-o smtpd_milters=inet:127.0.0.1:8891

(The milter on port 8891 is for opendkim signing)

Thus we do effectivly no checks on delivery from Mailman to Postfix and
leave it up to Postfix outgoing smtp to handle things like domain not found.

-- 
Mark Sapiro The highway is for gamblers,
San Francisco Bay Area, Californiabetter use your sense - B. Dylan
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[Mailman-Users] "host not found" or "account .. does not exist" when host or account does exist

[Jon Baron]

I run a mailing list with 4000 subscribers (jdm-soci...@sjdm.org). Every
time it sends mail to the list I get about 10 failure messages (completely
failure, not temporary failure that keeps mail in the queue) saying that
the host is not found or the email address doesn't exist. I can often find
the host with the (linux) "host" command, and the email address checker
often shows that the address is valid. The same email address that failed
usually succeeds on the next post.

I would like to keep these messages in the queue if possible, or maybe
allow more time for finding the host, or something, before giving up on the
first try. I cannot find a configuration option.

Jon
-- 
Jonathan Baron, Professor of Psychology, University of Pennsylvania
Home page: https://www.sas.upenn.edu/~baron
Editor: Judgment and Decision Making (http://journal.sjdm.org)
Associate webmaster: sjdm.org
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[Mailman-Users] Re: AT&T RBL update

[Morris Jones]

On 3/31/2021 10:22 AM, Jayson Smith wrote:
On another note, I use MXToolbox to monitor my IP's RBL status, so I 
knew Linode was on Ucepretect level 3. I'm sorry to know Digital Ocean 
is also on that list. It just means I can't in good faith tell someone 
I'm not on any RBL's because they can do a quick check and find out I 
am, in fact, on one. To a poorly programmed automation or an ignorant 
human, an RBL no one pays attention to is still an RBL.


Yes, I'm a Linode customer. When I was most recently blocked by AT&T, I 
brought that up with Linode support. They gave me a fairly informative 
response:



We understand and share your concern regarding the recent listing of our ASN 
with UCEPROTECT's Level 3 service. After researching the details of the 
listing, we have determined that the Level 3 service offered by UCEPROTECT is 
not reputable, and we will not be paying for delisting from their service.


So their research must have concluded that they're holding the ISP 
hostage for a payment. They added:



We have found that customers reaching out regarding this listing are really 
being rejected by internal RBLs of mail providers, but are reaching out because 
the UCEPROTECT listing is the only public service where they were able to find 
their IP address listed.


... which described my request exactly.  :(

Best regards,
Mojo
--
Morris Jones, Monrovia, CA
BridgeMojo 
Old Town Sidewalk Astronomers 
Mojo's Blog 
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[Mailman-Users] AT&T RBL update

[Jayson Smith]

Hi,


Great news! Not forty-eight hours after my first Email, my IP is 
unblocked! Then a few hours later I received an Email from the AT&T 
Postmaster saying my IP will be removed from their RBL within 24 hours 
of this letter. Go figure.



On another note, I use MXToolbox to monitor my IP's RBL status, so I 
knew Linode was on Ucepretect level 3. I'm sorry to know Digital Ocean 
is also on that list. It just means I can't in good faith tell someone 
I'm not on any RBL's because they can do a quick check and find out I 
am, in fact, on one. To a poorly programmed automation or an ignorant 
human, an RBL no one pays attention to is still an RBL.



Jayson

Jayson


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