some out going email not delivering

[pickman]

Hi,

 

got an issue with some email not delivering mostly BTInternet and AOL.

 

on mx toolbox the only warning i have are below.

 

My A records for mail point directly to my mail server.

 

smtp mail.thehazeleyacademy.com Reverse DNS does not match SMTP Banner More Info

smtp mail.thehazeleyacademy.com Warning - Does not support TLS.

 

looking at FQDN on the exchange and have asked my external support company about changing them as they are already populated with the server name.

 

error message on smoothwall is delivery temporarily suspended: host mx.bt.lon5.cpcloud.co.uk[65.20.0.49] refused to talk to me:

 

other mails are going through ok

[ZeroHour]

I know some can block if the rDNS is not correct. Its an *old* way to spam filter but some still use it.

[smarties11]

Your reverse DNS is correct, i.e. 217.33.213.214 has a reverse DNS of mail.thehazeleyacademy.com - however, when connecting to your SMTP server it is reporting smoothwall.HazeleyAcademy.internal. You need to change the setting on your SmoothWall box so that it reports mail.thehazeleyacademy.com. You can do this on the Email tab, under SMTP relay. Click advanced, and click the option 'user defined hostname' instead of 'use system hostname'. Then type mail.thehazeleyacademy.com in the field presented and save.

 

*edit* Sorry, I forgot to add - some SMTP servers check to ensure that the reverse DNS matches what is being reported by your SMTP server in the banner header, and reject if they don't. Making the above change will ensure they match.

 

Hope this helps!

Edited May 2, 2017 by smarties11

[pickman]

Thanks yes that solved it.

[smarties11]

No problem, pleased it worked for you!