I am running Windows Small Business Server 2008 which has been fine for a couple of months. Recently I have been getting weird mail delivery issues. I get the occasional spam message, but nothing for hours. When I restart the server or the exchange services, mail delivery carries on as per normal and then stops again for hours. I cannot see anthing in the logs related to the error, my queues are clean and the diagnostics tells me nothing. I do get errors about my SSL Certificate whish I still need to get and it compains about forefront security having expired, but this has been so for a while before the problem occurred. Do any of the experts have any ideas. I have a site similar to my system that does not exhibit the same problem although they are using the POP connector whereas mine is direct SMTP transfer.

I would rip out the Forefront Security product if it has expired. An expired product can actually cause more problems. When you have no email coming in, can you telnet to the server on port 25? If so, if you issue a ehlo does Exchange respond? Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Simon... When I telnet onto Port 25 and issue a helo and ehlo, the server responds without any indication of problem. Yesterday however, one of my clients sent me this bounceback host mail.xyz.co.za [111.111.111.111]: 452 4.3.1 Insufficient system resources I have more than sufficient memory and storage on the server so I have no idea what they mean by this. It is also the first and only time I saw it.

FYI... I removed Forefront, restarted, received 3 messages and back to Square1

The NDR is the key to this mystery, which is why I got you to try telnet. Insufficient system resources doesn't actually mean processor, RAM etc. It can mean other things. How much disk space is on the server? I mean in the drive where Exchange is installed. What you may consider plenty and what Exchange does can be different things. You might think that 2gb is enough, but for Exchange, it wouldn't do. It sounds like back pressure is at play. This article goes over the symptoms. http://exchangepedia.com/2007/03/exchange-server-2007-transport-452-4-3-1-insufficient-system-resources.html However don't make the changes just to resolve this issue, unless you have configured things incorrectly to begin with - such as trying to install too much in a small partition. If space was ok and things have dropped, then you should investigate why. Look for the underlying cause, rather than just trying to deal with the immediate problem, as it could save you from additional issues. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.

Hi Simon... Thank you for the reply. You mentioned the resource issue, and I have 14Gb on the drive and have about 8Gb of ram available. But your reply did make sense and the support document made me think back to dumping a stack of ghost system images onto the server. It probaly did not rear its ugly head streight away, But I think it may be a disk space issue... I am now moving the images onto another drive and will monitor it over the next 24 to 48 hours. If the problem persists, I will let you know. If it fixes the problem, I will let you know.