Topic: Sorry,_I_wasn't_able_to_establish_an_SMTP_connecti on._(#4.4.1)

[mr_tariqahmed]

hi,
   I have SME 7.4 and auto updated to 7.5. I transferred my domain hosting from one ISP to another and it took 12 hours to update its name server and mx record information on registrar and internet DNS resolution.
After the update complete I change the gateway in SME to new ISP and it started working fine but after almost 5 hours SME stopped 80 % incoming and outgoing emails. I checked "tail -f /var/log/qmail/current" and found one message "Sorry,_I_wasn't_able_to_establish_an_SMTP_connection._(#4.4.1)" for each delivery except few successful deliveries.

I searched on google for this error and found this is DNS error and assigned ISP's DNS IP on SME but no success then I removed DNS from SME as it has ability to resolve the names.
SME server is updated to all latest updates.

Any idea or suggestion ?

Tariq
 

[CharlieBrady]

I searched on google for this error and found this is DNS error ...

You were misinformed.

Any idea or suggestion ?

The most common cause of this problem is your ISP filtering outbound port 25 TCP connections, and the most common way to solve the problem is to route all mail via your ISP's mail server. Read the User Manual for instructions on how to do that.

[soprom]

I've got this problem when I used opendns as my only dns servers on an upstream gateway. Local dns on this gateway was not resolving my local smtp server name and those error messages showed up for local domains not properly referenced in "domains" (server-manager). 

[CharlieBrady]

I've got this problem when I used opendns as my only dns servers on an upstream gateway.

Why were you using opendns?

and those error messages showed up for local domains not properly referenced in "domains" (server-manager). 

Why do you have local domains not properly referenced in the "domains" db?

[soprom]

I was trying opendns to limit usage of radio and tv on internet at a community center. So I activated opendns filtering options...

Then a user calls me complaining about not being able to send emails (the server logs showed those error messages). And guess what? She was listening to radio!

I put back the local dns pointing to the gateway (pfsense with sme7 in dmz/lan) in the gateway's dhcp server.

And second problem was caused by a hostname not defined in the domain section although is was defined in the hosts sections. Not sure if it was causing those errors tho.

[janet]

soprom

I was trying opendns to limit usage of radio and tv on internet at a community center.

Consider using Dansguardian to do that.
Block access to sites and file types.