Interesting Email problem

[MattDLEA]

So one of our support staff users her own laptop in school which is no problem with outlook on.

she is using her .ntlworld address to email people.

With this address in school she can email fine except to hotmail addresses and she gets this bounce back error

This is the mail system at host know-smtprelay-11-imp. I am sorry to have to inform you that your message could not be delivered to one or more recipients. The message is attached below. The remote mail system said: SC-001 (COL004-MC1F37) Unfortunately, messages from **.***.**.** weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.

But at home this works fine.

If she used Gmail in school to email a hotmail address this works fine to.

 

Im guessing its not smoothwall that is blocking this, would it be BT who provide our schools internet thats causing this?

[W32Jbot]

Have you checked your IP for presence on any DNSBL's?

 

try: http://mxtoolbox.com/blacklists.aspx

 

Or I find this is a bit more comprehensive: http://www.dnsbl-check.info/

Edited December 9, 2015 by W32/Jbot

[bald_pig]

Looks like hotmail have blacklisted your IP?

[sllorep]

For email issues, MXToolbox is brilliant.

If you haven't already, put your domain name or IP in here to check for black listing:

Email Blacklist Check - See if your server is blacklisted

[MattDLEA]

Putting the external IP into mxtoolbox we are on 3 blacklists

Baracuda

RATS

Spamhaus Zen

[W32Jbot]

All of those are easy to get removed from, just follow their removal procedure.

 

You should also use the other DNSBL checker I gave you as it checks some other lists that MXToolbox do not.

 

You won't have been blacklisted for no reason though, and most DNSBL operators will want to know what action you have taken to remediate.

[sllorep]

Make sure that your Exchange server isn't an SMTP Open Relay.