List users from different domains getting blocked.
I am running MM3 and have a list that has users from different organizations and email domains.
So let's say I am orga.com and hosting mailman Bill is borg.com Cindy is mew.com
When Bill sends a message to my MM3 list it gets sent out, However, cindy's email system rejects it cause it sees the message is sent from Bill@borg.com but it came from my MM3 server which is under orga.com, so it rejects it.
I have been told more organizations are checking this and starting to reject these types of messages and also we could get blacklisted because it looks like we are spoofing.
The only solutions I can think of are:
-Have the receiving organizations whitelist my server, but that is probably not feasible. -set the list to anonymous..... But then you don't know who sent the email.
Anyway around this? or is there a way to have the sender's email included in the list message but keep the list anonymous?
or am I missing something else?
and if I send amessage from my organaxztion to MM# it will go out to the peopl n the list, and if and some of those people are at other organizations. When the recive the email, sometoimes their mail system reject it with a DMAR message. I have been told thisis beacue the other organazatione dmeail system sees I snet the message
"bob" == bob B via Mailman-users <mailman-users@mailman3.org> writes:
bob> I am running MM3 and have a list that has users from different bob> organizations and email domains. So let's say I am orga.com and bob> hosting mailman Bill is borg.com Cindy is mew.com
bob> When Bill sends a message to my MM3 list it gets sent out, bob> However, cindy's email system rejects it cause it sees the bob> message is sent from Bill@borg.com but it came from my MM3 server bob> which is under orga.com, so it rejects it.
Set up 'DMARC mitigation' in the lists setting to 'Replace From: with list address'
That should fix it.
Peter C
On 12/14/23 14:19, bob B via Mailman-users wrote:
I am running MM3 and have a list that has users from different organizations and email domains.
So let's say I am orga.com and hosting mailman Bill is borg.com Cindy is mew.com
When Bill sends a message to my MM3 list it gets sent out, However, cindy's email system rejects it cause it sees the message is sent from Bill@borg.com but it came from my MM3 server which is under orga.com, so it rejects it.
You need to apply DMARC mitigations. Normally mitigations are only applied if the From: domain publishes DMARC p=reject or p=quarantine, but recently this has become problematic. For example, gmail.com pubpishes DMARC p=none yet google servers effectively apply p=reject to mail From: gmail.com.
Mailman >= 3.3.9 and Postorius >= 1.3.9 allow setting dmarc_addresses to a list of email addresses and regexps matching addresses and domains to which DMARC mitigatations will be applied regardless of puublished policy. For older releases and for cases where domains are not known in advance one can always set dmarc_mitigate_unconditionally True to apply mitigations to all mail.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
participants (3)
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bob B -
Mark Sapiro -
Peter Chubb