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kill open relay exch 5.5 multi domains

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7 replies

by charger media

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I need to disable open relay on Exchange 5.5, Win2k network Active Directory. We have multiple domains going through the mail server.

I tried going into IMC, Routing, set each domain's "sent to" and "route to" its domain name, then went to routing restrictions and set to only allow hosts that have successfully authenticated. This worked fine to kill open relay, but then the clients could not send or recieve emails beyond the mail server.

Do I need to go into "Connections" in IMC and set have all hosts authenticate then instruct the clients to make changes in their email client to accommodate this?

Suggestions on how to conquer this are greatly appreciated!

7 replies

by charger media

Thanks, although that article pointed me in the right direction, it did not solve the problem. I found no difinitive solution for multiple domains using POP3. I can't restrict to hosts and clients IP addresses as clients are using dynamic IPs.

by machinetype

In Outlook express goto the tools/accounts section and look at the properties of the account. On the servers tab tick the "My Server Requires Authentication" setting, you should be able to leave the settings section alone.

Hope it helps.

by giles

I had a similar problem with a number of linux mail servers that had to connect to an exchange server and required the ability to relay mail, but did not want the outside world to be able to relay from the server (who does?)

Easiest solution I found was to install a second NIC with a new IP address. Relaying was set in the IMC properties so that you could relay if you connected to one IP, but not if you connected to the second IP. From here I then configured our firewall to NAT all trafficfrom the outside world (smtp etc) to the IP that could not relay mail.

end result - internal / trusted users / clients could relay from the 'trusted' IP address, but external / untrusted clients could not relay from the interface connected to theoutside world

Hope this is of some help.

by charger media

I found that the problem is between Exchange 5.5 and Pix firewall. Pix Mailguard (SMTP filter) is on by default and breaks up Microsofts authentication packets.

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