Unknown username or bad password - InetInfo.exe – ADVAP

Posted on 2010-08-24
Last Modified: 2013-11-30
Hi All,

This is something that I recall seeing a bit as far as in forums, but never really found a solution for .... I have multiple SBS 2003 boes for various clients who at times get a flurry of what looks to be attempts to relay mail via smtp with inetinfo.exe. We see multiple Event 529 failed attempts in eventviewer.

I have gone through but this is really identifying the culprit, and I would prefer to block any such attempt.

I am not an exchange expert my any means, but one would think that if I am receiving all email through a third-party, then I should be able to apply some type of filter stating that all other attempts should not be accepted? Right? How do others deal with this same issue, or is this just apart of SBS 2003 life and we should just keep passwords strong?
Question by:Flipp
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LVL 58

Accepted Solution

Cliff Galiher earned 500 total points
ID: 33516971
It is a part of *any* SMTP server's life. They have to accept connections to properly send and receive email, thus invalid attempts can be made.
Now you *can* use an edge firewall (which you should have anyways) to restrict SMTP connections from the outside if you are using an MX relay service such as postini, mxlogic, or dyndns MX services. That will prevent the connections from reaching your SBS box in the first place thus no events logged.
But as long as your SBS box is reachable, it will log failed attempts to relay. Yes, Exchange allows you to restrict which IP addreses can send and receive, but connections outside of those filters will still log failed events, which is what I suspect is happening now, so you won't be fixing the problem you want to fix, which is reducing the number of events you are seeing.

Author Comment

ID: 33517084
Thanks Cliff.

We currently do use DynDNS mailhop service, but not an edge firewall. My initial concern is always security, but also want to ensure that the SBS box is not bogged down handling the flurry of SMTP requests that seem to flood in.

I think we are back to, 'a day in life of an exchange server' as far as these events are expected and a fact of life. Are there any recommendations as far as reducing logging or any other type of filtering?
LVL 58

Expert Comment

by:Cliff Galiher
ID: 33517380
Except for the suggestion I already made that you should have an edge firewall (and you DEFINITELY should!), none. That is your first and best line of defense.

Author Comment

ID: 33517774
Thanks Cliff. I have not heard of this product - any recommendations for this?
LVL 58

Expert Comment

by:Cliff Galiher
ID: 33518306
A good edge firewall? Calyptix, Cisco, Sonicwall, Watchguard, among others. I listed in alphabetical order so as not to imply favoritism. But all make perimeter security appliances targeting the small business space and can filter on a protocol level such as SMTP.

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