2 weeks ago my vps server was down inexplicably. After rebooting Gmail clients could not send(SMTP) or receive emails(POP3). All login details were confirmed as correct. I have confirmed all ports are open and can send and receive emails from all virtual servers in virtualmin. I have checked that there are no firewall is blocking pors 25, 995 or 465, this also confirmed by the VPS provider. I used Nmap to check for closed ports all seems OK. Initially I could receive emails via POP3 on one virtual server if I used the VPS server address as the address instead of the virtual server mail.xxxxxx.com. I assumed that because Centos 8 was EOL maybe that was the issue. I did a fresh install of Centos 7 and migrated the virtual servers. Situation remains the same. I can send and receive emails via Usermin, one of the virtual server websites has a plugin that uses SMTP and can send emails too using the virtual server credentials. Gmail returns the below errors still. Is this a known issue? I have looked at the log files and seem to have hundreds of failed authentications every few minutes for non existent email accounts(I think this is normal, failed logins from hackers). Anyone have an idea what could be the issue?
Gmail error (Server returned error: “Connection timed out: There may be a problem with the settings you added. Please contact your other email provider to verify the correct server name and port.”
Couldn’t reach server. Please double-check the server and port number.)
Nmap details:
Not shown: 844 closed tcp ports (reset), 127 filtered tcp ports (no-response), 15 filtered tcp ports (host-prohibited)
PORT STATE SERVICE
22/tcp open ssh
25/tcp open smtp
53/tcp open domain
80/tcp open http
110/tcp open pop3
143/tcp open imap
443/tcp open https
465/tcp open smtps
587/tcp open submission
993/tcp open imaps
995/tcp open pop3s
3306/tcp open mysql
10000/tcp open snet-sensor-mgmt
20000/tcp open dnp
Nmap done: 1 IP address (1 host up) scanned in 11.03 seconds
I cannot find any mention port 25 in master.cf or even port 465. My config file ends at line 134 yet when I try to filter with a term it gives me items with lines above line 134 e.g line 230, etc
You should only have the 1st line un-commented - the rest should have a “#” before them.
If that is the case - which I expect it to be - then Postfix is only listening on Port 25 (SMTP port IS port 25). In your original post and in the Wormly test results, you are\were trying to connect via port 465 (which is SMTPS). Which isn’t going to respond as Postfix is set to respond on SMTP (Port 25).
@sejo2001 - I believe your Postfix installation is ONLY setup for SMTP (aka Port 25). You appear to be having issues connecting to it on SMTPS (aka Port 465) - never going to work until master.cf is altered to tell PostFix to also use SMTPS.
SMTP (port 25) receives emails perfectly well. SMTPS (Port 65) doesn’t. Why? Most likely there is no entry in the “table” in master.cf for SMTPS and therefore Postfix just ignores the incoming EHLO command.
@Dibs I have been using the same settings for almost one year now, just puzzled that suddenly Gmail will not use POP3 or SMPT credentials. That is both dovecot and postfix, the odd thing is I can see dovecot logs showing the thunderbird POP3 logins but none for any of the gmail attempts. I am not sure if I should post logs here because there are client emails listed and IP addresses.
