Internal/External Email with ISA and Exchange 2000

[Ueline]

Thanks to everyone for interesting posts and making this site great.

Now...
We use Exchange 2000 (V6.0 build 6249.4 Service Pack 3) on Win2000 Server for internal email. We'd like to use it for external email but have been having some problems (not all caused by ourselves) configuring this. We also use ISA Server on Win2000 and have now got as far as being able to send external email. When it comes to getting replies/messages in it's another matter. If I reply to a successful external email then after about a day I get a reply saying the mailbox is full. I've read various things about this. For example

Possible Cause: This code may be caused by resource problem such as a disk full condition. This code may also occur if your Simple Mail Transfer Protocol (SMTP) queue is on a File Allocation Table (FAT) partition and the service has reached a Windows-imposed limit on the number of concurrent file handles that can be opened by the SMTP Service. In this case, instead of receiving a disk full error, you might be receiving an out of memory error.Troubleshooting: Make sure you have sufficient disk storage, and try to operate your Exchange Transport queues on an NTFS partition.

Needless to say it's NTFS.
I've just set up Diagnostic Logging for exchange transport to see if that helps.

I am probably barking totally up the wrong tree as I'm very new to this. If you think you may have any ideas to help resolve this then please bear this in mind when you reply

Cheers.

[Ric_]

Is the mailbox full? Try disabling the maximum mailbox size on your mailbox and retry.

You could also test communication with your exchange SMTP server using telnet (port 25). Just stick a laptop on the 'outside' of your ISA box.

[DMcCoy]

Not used exchange too much, although this is about to change. Just an idea, how big is the database? And how does the mail get out via isa? Does the isa box resend or direct the data externally. Does it forward the data to a smarthost for delivery or attmept direct delivery?

[steve]

I see you're also in west yorks. Are you using the RBC, yhgfl? Or a another broadband provider for your email/internet access? If yhgfl, contact me I can give you much more specific help.

Check where inbound email is being sent to using nslookup from the command line:
nslookup
set type=mx
your.domain.name
(exit to quit)

This will tell you where mail is sent to. Does it go direct to your ISA server or a mail relay?

Either way you need to ensure you have port 25 on your ISA open for clients or the relay. If its a relay you'll only need to allow one incoming IP the ability to access your exchange server, if its direct you need to allow all IP's to access it.

Check this both on the ISA settings and in the Default Virtual Server Properties - Relay Restrictions.

http://blogs.technet.com/jhoward/default.aspx has some excellent videos on configuring ISA 2004, exchange 2003 but still apply to previous versions.

[Simcfc73]

Heres one I just thought of which may have been a issue with my network.

Do you have a _ or a - in the DNS name?

Just a longshot but it may be worth looking at.

[Ueline]

Thanks to everyone for the advice. Port scanning I found that there wasn't any SMTP traffic even when I bombarded with email. Turned out that BT had mis-spelt the relay and it's only taken 2 years for them to realise this despite our constant whinging. It impossible to calculate the number of man-hours wasted on this Anyhow it's sorted now.