i get emails but i can't send emails!

esmailelbob

Hi i finally setup mailcow (After literally half of a day) and i can get emails (thank god) but i can’t send emails to gmail/mailfence/tutanota (i can send locally tho) so how to solve it?

i made my dns same as recommended for me in config > mail setup > action - DNS

PS: i get error in my TSLA DNS: Unknown banner: ""

Joshua2504

what does mail-tester.com say?

esmailelbob

Joshua2504 i tried but because i get nothing (can’t send anything and yes i waited over 5m) nothing shows…

MAGIC

Which hoster do you use?
Maybe port 25 outbound is blocked

esmailelbob

MAGIC it’s a self hosted machine and i opened port in my router

BusterB

Were you able to send outbound emails from a mail server before? The reason I ask is my (and I suspect many) ISPs block port 25. I send outbound email over a different port # and to do this I use a mail relay with a provier over port 2525. Mailcow has a tab/setup to specifically handle this (Routing -> Sender-Dependent Transports). While I believe you can probably still send it out over port 587, the second thing to consider is actually reputation, especially with Gmail Using a commercial relay (a good one) is more likely to score better on the “not spam” lists and for me I noticed a difference whereby when folks were previously “not getting my emails”, now everything gets sent out successfully every time.

Does the Queue Manager show/hold your outbound emails? (i.e. are they getting out but being blocked down-stream?)

Any warnings or errors in your Mailcow UI log files? (i.e. Configuration -> System Information -> Logs -> Postfix)

A third thing to consider are the entries in your (hosted) upstream DNS provider. There are multiple settings to set, such as DKIM, TLS, CNAME and MX records. (I have about 18 just for mail for one host – seriously!) A single CNAME entry is not sufficient… Let me know and I can post what I use, though most of it is in the mailcow documentation.

esmailelbob

BusterB Hi, sorry for late reply

Um the good news is i’m now sure it’s problem with my 25 port the bad news is it seems it works fine?

root@debian:~# telnet 192.168.0.101 25
Trying 192.168.0.101...
Connected to 192.168.0.101.
Escape character is '^]'.
220-mail.esmailelbob.xyz ESMTP Postcow
220 mail.esmailelbob.xyz ESMTP Postcow

because i got Delayed Mail (still being retried)

This is the mail system at host mail.esmailelbob.xyz.

####################################################################
# THIS IS A WARNING ONLY.  YOU DO NOT NEED TO RESEND YOUR MESSAGE. #
####################################################################

Your message could not be delivered for more than 4 hour(s).
It will be retried until it is 5 day(s) old.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<test-k91q5asu6@srv1.mail-tester.com>: connect to
    reception.mail-tester.com[94.23.206.89]:25: Connection timed out

so yes it’s problem with my 25 port but for some reason when i check it out online or via telnet it works fine so maybe problem elsewhere?

about Routing -> Sender-Dependent Transports i’m not sure what to do there so could you explain more?

about queue manager yes all of my sent emails i have the word deferred on them

about logs i get no warnings when i send email except i get connect to smtp2.mailfence.com[212.3.242.79]:25: Connection timed out

Last but not least about dns i have the recommend dns for me that are in config -> mail setup -> action (DNS) although i have error with one of dns record in TSLA dns i get php error but yes you can help me and give me dns records as example so i mimic them for my server

PS: when i try to telnet it it hangs out so something in my machine that does not allow 25 ports? but i do not have firewall tho
root@debian:~# telnet smtp1.mailfence.com 25 Trying 212.3.242.78...

esmailelbob

good/bad news depends on you, i think i fixed my port issue (not sure how but it works now) and i get new error message

C29DB461C9B: to=<f@gmail.com>, relay=none, delay=1050, delays=1040/0.11/10/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=gmail.com type=MX: Host not found, try again)

esmailelbob

esmailelbob nvm i get old timeout error back

esmailelbob

Finally, finally i knew why it happens. it’s my fucking ISP they block it by default and charge money for it’s service and even if i want it i can’t as service is not available at meantime

god i hate them so much, thanks for help tho

BusterB

Yes, per above, you were able to connect to port 25 on your LAN but not via the WAN.

Use a service like DYNU. I use them for dynamic DNS, email backup and SMTP outbound relay services. Basically, their email backup is an MX relay, which is great because if my server or router goes down, they will store/queue any incoming emails, plus they include an optional anti-SPAM service built-in (I use it – it’s great). The outbound relay service allows me to send and receive emails over port 2525 via mailcow’s “sender transport” setting. I only pay $10 per year for each service, which is very reasonable, considering I have a mail relay/backup, anti-spam and dynamic DNS all in one place. In my opinion it’s definitely worth it! Highly reccomend!

esmailelbob

BusterB I used to use them before i jump with duckdns.org (Because they are open source and i like supporting these kind of projects) but darn it! seems i will get back with Dynu >_<

Now my question is, i will sub to them okay i give up fuck my ISP so if you can help me like step by step guide to setup? maybe in dms or take my email (not my mailcow email for obvious reasons)

And to make it clear i can get emails but i can’t send emails so dynu will fix this problem? let’s just hope my ISP did not block 2525 too

bokbok

BusterB hey can u help me out

esmailelbob

UPDATES: first GOD DAMMIT FUCK MY ISP SO MUCH

they block port 2525 too (yes same old timeout pal!) good news tho they do not block 26 port and it works it works!!!!

so how i did it (for future me or someone asking) i went to https://www.dynu.com/en-US and went to emails (https://www.dynu.com/en-US/Email/Outbound-SMTP-Relay) and bought it (because i thought @BusterB got all of these stuff for just $10 but turned out each cost 10 so i bought SMTP only (for now at least) and i went to routing in mailcow and i added info that displayed in my dashboard at dynu (Home > Control Panel > Email Services > Manage Email Service) and then i added this relay in to my mailbox in mailcow then i tested it and 26 worked

esmailelbob

hey @BusterB i looked into it more and sadly relay can see all of your emails via it’s logs (all) even if you used TLS so now i’m looking into something as hosting my own relay?

bokbok

hey im having the same issue
but my isp dont block port since im using a lenode to host it

BusterB

I’d start with the basics. Check your logs, starting with postfix then dovecot. Run internal checks to see how port 25 is responding to requests to it, then expand the checks to come from external hosts not on the LAN. Verify your firewall settings. Check if anything’s in the jail (e.g. you might have hit limits). Check for other blockages, such as for IMAP or POP’s ports – are they listening? I use Portainer to check each component’s status and logs – it gives good visuals for anything ‘glaring red’, plus you can manage the containers, jump to command-line and check logs easily.

For example,

Connect via SMTP (587)
echo “Q” | openssl s_client -starttls smtp -crlf -connect <yourhost.TLD>:587
Connect via IMAP (143)
echo “Q” | openssl s_client -starttls imap -showcerts -connect <yourhost.TLD>:143
Connect via HTTPS (443)
echo “Q” | openssl s_client -connect <yourhost.TLD>:443

You basically have to go through the process of elimination at each “choke point” in your end-to-end mail implementation since there are many things to consider. The port might be open, but other things could be going on, so you just have to go through the whole pathing, unfortunately.

bokbok

BusterB i did all of that everything is working find