Exchange HELO security question 2

[Topkapi]

I've just started doing some work for a small company which recently installed SBS2003. They have a very basic ADSL router set up to forward SMTP traffic to the server. If I telnet on port25 to the external IP of the router I see the same response as if I do it on the LAN.This shows pretty full information i.e. that it is an Exchange server, its version number etc.

Is possible to change/restrict this HELO info as I imagine this is potentially useful to spammers, hackers etc.

Thanks in advance

 

[Grenage]

http://www.msexchange.org/tutorials/change-POP3-IMAP4-SMTP-banner-Exchange-2003.html

Carlsberg don't run I.T departments, but if they did they'd probably be more fun.

 

[Topkapi]

I must need to improve my "Googling" skills.

Have a star!

Thanks

 

[Grenage]

No problem, I guess the key word is "banner", which might not be obvious unless you were already aware!

Carlsberg don't run I.T departments, but if they did they'd probably be more fun.

 

[58sniper]

Don't change the ehlo banners unless you want to increase support costs when dealing with PSS. There is really no reason to change that.

Pat Richard, MCSE MCSA:Messaging CNA
Microsoft Exchange MVP
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt

 

[Topkapi]

Hi Pat

Your reply seems to imply that the article on MSExchange.org is inherently risky. If so can you please explain why.

Also why do you not believe that, if implemented correctly,that the result would be beneficial?

Grateful for any extra insight.

Thanks

 

[58sniper]

Changing the banner does nothing for security. Knowing a version number doesn't show which hotfixes are installed. Or what IMF options are enabled. It merely makes troubleshooting harder.

And, as the article mentions, POP3 and IMAP are disabled by default, (and should be kept that way).

Keeping the server up to date with security patches, as well as a correctly tuned firewall will go MUCH further than merely masking a version number.

Pat Richard, MCSE MCSA:Messaging CNA
Microsoft Exchange MVP
Want to know how email works? Read for yourself -

http://www.ietf.org/rfc/rfc2821.txt