Email issues - bad IP reputation?

[EddScott]

A friend is having problems with his emails on his laptop.

His first account is hosted by some local company

He has two accounts and when using outlook he gets the following message

"554 Sending Address not accepted due to spam filter"

And in Outlook Express it says

"554 Your access to this mail system has been rejected due to the sending MTA's poor reputation"

His other account which is a BT account

Outlook says

"The connection with the server was interrupted"

When sending and receiving using the BT account in Outlook Express its fine.


Now, am I right in saying the that the 2nd account (the BT one) is probably something simple and maybe no more than a settings issues. The first account sounds much more serious and seems to be seen as some sort of spam??

Its something I've never come across before. Any ideas?

 

[Skidilliplop]

Either IP reputation or reverse DNS. Quite a lot of spam filters do a reverse DNS lookup on inbound connections to verify the sending server. That tripped us up when we changed the route outbound SMTP went out. It egressed from a different NAT and source public IP, which didn't reverse resolve correctly and resulted in blacklist headaches

 

[PistolPete]

Check to see if the user can authenticate to each server before sending

If you are not using your ISP outgoing SMTP server then it's likely that you'll need to authenticate to the SMTP server you are using.

There is a good chance the SMTP server is rejecting the first (sending address) as you've not authenticated to the server and your From: address is not on the server local tables so it thinks you are trying to use it as an open relay.

Second one is again probably rejecting due to not authenticating and the server is using some kind of blacklist that highlights the sending IP as being from a dynamic pool and wont relay as 99% of dynamic users should be going via their ISP SMTP server.


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