Sending email via DNS

  • Thread starter Thread starter Donald R. Millik
  • Start date Start date
D

Donald R. Millik

I have an Exchange server 2000 and we use DNS to
distribute the internet e-mail.

It stopped sending e-mail yesterday, but does receive it.

I talked with a tech at my ISP and he said that they have
blocked port 135 because of the blaster worm and that this
is the problem with my e-mail.

Does DNS use 135 and does this make sense?

Thanks.

Don
 
Does DNS use 135 and does this make sense?

No, it does not. And no, it does not.

What happens when you do an nslookup from your mail server? Are you able to
resolve names to addresses?
 
Hi Don,
DNS use TCP and UDP ports 53. Go to start, run type cmd, then click ok.
type in nslookup hit enter
type set d2 hit enter
then type set type=mx then hit enter
then type in yahoo.com then hit enter
do you see the mail records listed?
Copy and paste it here and we can tell you whats going on.
You can also open another command prompt, type tlenet mailb.microsoft.com 25
hit enter, Do you se a banner at the top?
 
DRM> It stopped sending e-mail yesterday, [...]

What are the error messages ?
 
I have an Exchange server 2000 and we use DNS to
distribute the internet e-mail.
Click to expand...

DNS resolves host names to IP's and IP's to host names. It doesn't
distribute mail.
It stopped sending e-mail yesterday, but does receive it.
Click to expand...

DNS didn't.
I talked with a tech at my ISP and he said that they have
blocked port 135 because of the blaster worm and that this
is the problem with my e-mail.
Click to expand...

Your tech support is an idiot. Come to think of it, much of the tech
support I deal with falls in this category as well.
Does DNS use 135 and does this make sense?
Click to expand...

DNS doesn't use port 135, and it doesn't do mail. In addition, *most*
mail programs don't use port 135 either.

But, you may not be too far off and your tech support may be close to
correct even though they don't know it. Port 135 will block NetBIOS,
and if you have no DNS or an improper DNS configuration and your
system previously worked with NetBIOS broadcast resolution, then port
135 being blocked *might* cause your mail to not get through.

Start by fixing the DNS so you can ping the Exchange server by name
and resolve its IP address. This is the FQDN, ie:
mail.sample.domain, not the name alone.

Then, make sure port 25 and 110 are open for TCP, as well as 53 for
both TCP and UDP. These are the ports for SMTP (Outgoing mail), POP
(Incoming mail) and DNS. From there, it's making sure Exchange is
configured properly.

Also, your tech guys should have been blocking port 135 from external
access ever since you connected to the internet, not adding it at this
time. Plus, thye shouldn't block it internally if it's needed
internally. Find new tech support people that can manage firewalls
and routing.

Jeff
 
Check to make sure that your virtual SMTP server is started - check the
queues. I'm presuming you're using forwarders in your internal DNS server to
resolve external names - you can also specify specific DNS servers to use
for lookup within the SMTP virtual server in Exchange System Manager.

Mail uses port 25, port 135 has nothing to do with it.
 
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