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Ram_75183's avatar
Ram_75183
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Feb 14, 2012

BIG-IP LTM to Exchange 2010 starttls not working for clients

Hi,     I have a pair of exchange servers behind a pair of BIG-IP LTM servers. When connecting clients directly to the exchange servers they can connect to SMTP 25 using TLS and send email.   ...
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Ram_75183's avatar
Ram_75183
Icon for Nimbostratus rankNimbostratus
Feb 14, 2012
Turns out that the cisco firewalls where using smtp inspection to disable starttls. I managed to get this turned off and al the emails went through.

 

 

If you are seeing XXXX's in your smtp logs then theres a good chance you have a cisco firewall inspecting your traffic and removing non rfc compliant smtp commands.