Permit or Proxy - SMTP

[Craig.Martin () faht scot nhs uk]

Hello,

I've just received a request from a colleague that looks after our exchange server.  Currently I have port 102 opened 
up to allow x.400 mail to be sent to a relay host.
But, the new request has asked for port 25 (smtp) to be opened up.  I'm a bit concerned about this and was wondering if 
anyone could (roughly) give some advice on the pitfalls in doing so.

My Gut reaction is to tie down the destination IP address for outgoing then just permit replies from the same external 
host and probably proxy it too.  However, my colleague has also asked if this could be allowed to all external hosts.  
This is the part that concerns me.

So...the question is...1) permit or proxy and 2) what's the risks here


Many TIA,


Craig.

__________________________________________

Craig Martin
IT Support Officer
Queen Margaret Hospital
Fife Acute Hospitals NHS Trust
Tel:  +44 (0)1383 623623
Fax: +44 (0)1383 627066
email: craig.martin () faht scot nhs uk
www: www.faht.scot.nhs.uk

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