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Exchange: Basic auth on port 25 - any reason for that?

Hello Experts,

I am quite new to MS Exchange and did deploy a Exchange 2013 recently which I am migrating right now to production.

When examining the receive connectors it occurred to me basic ath was enabled on Port 25 by default along with Windows Auth and Exchange server authentication.

On any other email system I would switch it off for security reasons, there is Submisson, 587/tcp for clients.

Is there any reason to keep basic auth switched on on port 25 smtp or can I safely turn this off?

Are there any other basic best practices to harden Exchange? (I know, this is a very wide area question but I ask it anyway :)

Daniel Helgenberger
Daniel Helgenberger
1 Solution
Simon Butler (Sembee)ConsultantCommented:
Exchange doesn't need to be hardened. The combination of IIS and Exchange on a dedicated Exchange server has (to my knowledge) never been compromised. Any issues with Exchagne have been down to poor password policies or stupid users and issues with IIS were caused by poorly written third party apps.

As for the authentication settings, they are used internally by Exchange. You could probably disable Basic authentication without any issues, although it isn't something I have routinely done.

Just because basic authentication is available on the connector doesn't mean it can actually be used for anything such as relaying.

If you do decide to disable it, restart the MS Exchange transport service afterwards, then watch your queues carefully.

Daniel HelgenbergerAuthor Commented:
Hello Simon, thanks for your input esp. on the 'hardening' part. Since I read some best practices at MS I have our Exchange servers already doing Exchange/IIS only. I can sleep better now!
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