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Enable outbound traffic on port 25 #6

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opened 2025-01-28 00:03:01 +00:00 by eric · 8 comments
eric commented 2025-01-28 00:03:01 +00:00
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AT&T blocks outbound traffic on port 25 to combat SMTP spam. Contact support and try to have this restriction lifted.

AT&T blocks outbound traffic on port 25 to combat SMTP spam. Contact support and try to have this restriction lifted.
eric added this to the Network Infrastructure project 2025-01-28 00:03:01 +00:00
eric added this to the (deleted) milestone 2025-03-02 19:46:08 +00:00
eric added this to the (deleted) milestone 2025-03-02 19:58:39 +00:00
eric commented 2025-04-30 20:26:28 +00:00
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This is becoming more relevant with active users on Discourse.

This is becoming more relevant with active users on [Discourse](https://discourse.eom.dev/).
eric commented 2025-05-06 17:31:40 +00:00
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I spoke with customer support for AT&T and was told that port 25 is not blocked on my network. I was told to switch to ports 465 or 587, which seem to be for relay traffic. I might have to do this - maybe it is the downstream email host that is blocking my traffic.

I spoke with customer support for AT&T and was told that port 25 is not blocked on my network. I was told to switch to ports 465 or 587, which seem to be for [relay traffic](https://docker-mailserver.github.io/docker-mailserver/latest/config/security/understanding-the-ports/#outbound-traffic-on-the-right). I might have to do this - maybe it is the downstream email host that is blocking my traffic.
eric commented 2025-05-06 17:37:17 +00:00
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Useful links:

Google sender requirements

DNS records for Email on Squarespace

Useful links: [Google sender requirements](https://support.google.com/a/answer/81126?hl=en&vid=0-147038839700-1476339994156&visit_id=638821495786426254-2784562162&rd=1#zippy=%2Crequirements-for-all-senders) [DNS records for Email on Squarespace](https://support.squarespace.com/hc/en-us/articles/31120985010957-DNS-records-for-email)
eric added a new dependency 2025-05-07 01:23:06 +00:00
#17 Use Helm to deploy Docker Mailserver
eric added a new dependency 2025-05-07 16:24:36 +00:00
#18 Remove gmail accounts from LDAP
eric commented 2025-05-08 21:12:10 +00:00
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I was able to get an AT&T representative to tell me that port 25 is blocked on residential connections. The saga continues.

I was able to get an AT&T representative to tell me that port 25 is blocked on residential connections. The saga continues.
eric removed a dependency 2025-05-08 21:12:36 +00:00
#17 Use Helm to deploy Docker Mailserver
eric added this to the 2025:Q2 milestone 2025-05-09 02:48:40 +00:00
eric commented 2025-05-22 03:04:18 +00:00
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I will likely be switching to Google Fiber soon, which does not have this same limitation.

I will likely be switching to Google Fiber soon, which [does not have this same limitation](https://support.google.com/fiber/thread/57794352/static-ip-port-25-open-outbound?hl=en).
eric commented 2025-06-17 19:06:21 +00:00
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I can confirm outbound traffic on port 25 is not blocked on Google Fiber. Email to iCloud was blocked due to an entry in Spamhaus, for which I have requested removal. I will have to allow time for the request to process before testing again.

I can confirm outbound traffic on port 25 is not blocked on Google Fiber. Email to iCloud was blocked due to an entry in [Spamhaus](https://check.spamhaus.org/), for which I have requested removal. I will have to allow time for the request to process before testing again.
eric commented 2025-06-17 19:33:40 +00:00
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Now it is rejecting due to DMARC policies...

host mx02.mail.icloud.com[17.57.152.5] said: 554
    5.7.1 Your message was rejected due to eom.dev's DMARC policy.
Now it is rejecting due to [DMARC](https://dmarc.org/) policies... ``` host mx02.mail.icloud.com[17.57.152.5] said: 554 5.7.1 Your message was rejected due to eom.dev's DMARC policy. ```
eric commented 2025-06-17 21:51:30 +00:00
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I modified the DMARC DNS record to mirror the example from this guied, and sending to iCloud was successful!

I modified the DMARC DNS record to mirror the example from [this guied](https://github.com/docker-mailserver/docker-mailserver/blob/master/docs/content/config/best-practices/dkim_dmarc_spf.md), and sending to iCloud was successful!
eric closed this issue 2025-06-17 21:51:30 +00:00
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#18 Remove gmail accounts from LDAP
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