Not Receiving External Emails

[mrforgetful]

We're having some problems with our email.

 

We run Microsoft Exchange Server 2003, all Windows Server 2003 R2 Enterprise Servers and Windows XP SP2 Clients.

 

If a user inside school sends an email to another user inside school the email works fine.

If a user inside school sends an email to a user outside school the email works fine.

If a user emails from outside school to inside school the email never arrives.

 

Where do I even begin?

Is it likely to be a problem within school setup or externally? I can't remember changing anything here.

[Geoff]

You need a copy of the bounce message the external user receives. You'll be able to pinpoint the mail routing based on the contents and origin of that bounce message.

[mrforgetful]

The notifications I got back when testing from Hotmail.com don't say a right lot, the email says

 

This is an automatically generated Delivery Status Notification.

 

Unable to deliver message to the following recipients, due to being unable to connect successfully to the destination mail server.

 

[email protected]

 

with an attachment saying

 

Reporting-MTA: dns;bay0-omc1-s14.bay0.hotmail.com

Received-From-MTA: dns;BAY126-W22

Arrival-Date: Fri, 9 Mar 2007 06:00:16 -0800

 

Final-Recipient: rfc822;[email protected]

Action: failed

Status: 4.4.7

[Lee_K_81]

Go to administrative groups - first adminsitrative group - servers - [server name] - protocols - SMTP - default SMTP server - right click, properties - access tab, click relay - what settings do you have here?

[mrforgetful]

Only the top radio button 'Only the list below' is selected, but there's nothing in the computers box.

 

I remember from my course (yeh so I should be able to fix this) about the awful traps in Exchange that can open it up to relay spam.

 

What should this page be set like?

[Lee_K_81]

I know that it possibly opens it up as an open relay but the only way i found to fix it was to tick "all except the list below". This should hopefully fix your problem, but if anybody knows how to not fail the "open relay test" but still allow email from external addresses to be delivered i would also be very interested.

 

This document explains more, but when i follow the instructions it stops any mail from outside of school.

 

http://technet.microsoft.com/en-us/library/6d2c9c82-bcc2-4261-a30d-90536577c873.aspx

[steveg]

On my configuration I have only allow the list below, and then further down, the tick box, "Allow all computers which successfully...." ticked. This is I believe the default setting, and seems to work ok.

 

Have you tried checking your network settings as well? Its possible external mail may not even be reaching your exchange server:

 

Have you changed the ip of the server recently? Changed any confiugrations on your firewall or Installed any security software on the server?

[Lee_K_81]

On my configuration I have only allow the list below, and then further down, the tick box, "Allow all computers which successfully...." ticked. This is I believe the default setting, and seems to work ok.

 

Breaks it for me.....

[DavidB4910]

Have you checked your exchange related services on the server?

[mrforgetful]

Trying both of those settings doesn't fix it I still get the mail returned. I'm using my Blueyonder account now as the returned mail is more informative as follows:

 

------ This is a copy of the message, including all the headers. ------

 

Return-path:

Received: from [172.23.170.145] (helo=anti-virus03-08)

by smtp-out4.blueyonder.co.uk with smtp (Exim 4.52)

id 1HQic3-0001wB-H0

for me@myschooladdress; Mon, 12 Mar 2007 11:22:47 +0000

Received: from [195.188.53.232] (helo=webmail.blueyonder.co.uk)

by asmtp-out2.blueyonder.co.uk with esmtp (Exim 4.52)

id 1HQic2-0006e2-TA

for me@myschooladdress; Mon, 12 Mar 2007 11:22:46 +0000

Received: from 195.188.173.194

(SquirrelMail authenticated user);

by webmail.blueyonder.co.uk with HTTP;

Mon, 12 Mar 2007 11:22:46 -0000 (GMT)

Message-ID:

<52282.195.188.173.194.1173698566.QFUUQ2xeS0h9RQ==.squirrel@195.188.173.194>

Date: Mon, 12 Mar 2007 11:22:46 -0000 (GMT)

Subject: Silly

From: [email protected]

To: me@myschooladdress

User-Agent: SquirrelMail/1.4.3a

X-Mailer: SquirrelMail/1.4.3a

MIME-Version: 1.0

Content-Type: text/plain;charset=iso-8859-1

Content-Transfer-Encoding: 8bit

X-Priority: 3 (Normal)

Importance: Normal

 

It's getting that way.

[mrforgetful]

Have you checked your exchange related services on the server?

 

Yeh they're all started, no errors in the Event Log either.

[OutToLunch]

May be barking up the wrong tree here but looking at the first error message you posted it suggests your mail server is not reachable from the outside world rather than it being something you need to dive in and shout at Exchange about, I'd look at networking problems first...

 

Was your mail server working as intended originally or are you in the process of setting it up?

 

If it was already working, is it possible your ISP has changed any settings on allowing inbound traffic on port 25?

 

If it is in the process of being set up, have you made sure you have forwarded port 25 to your server if using a router, or traffic is allowed if using a firewall etc...

[mrforgetful]

It's been working fine for a year, but it's not beyond the possibility I changed something, but then again it's also possible the ISP is broken, neither would surprise me.

 

The first message made me think it was an ISP DNS issue, but since the more detailed VirginMedia log it seems to get all the way to out webmail, or maybe it gets to webmail and can't figure out where that is?

 

But you can get to https://webmail.thorntongrammar.bradford.sch.uk which is the server so I'd guess that DNS is working. I'm confused.

[timbo343]

have a look at this...

 

http://www.visualware.com/demo/index.html

 

you might want to look at visual route for where your email domain is. It looks to me that your IP isnt resolving to a DNS.

 

I tested 195.188.173.194 and didnt get any domain names, but when i tested ours, all the domain names were there.

[Lee_K_81]

is the email being recieved by your exchange server? i.e does it show up in the "message tracking center" under tools.

[mrforgetful]

The only emails doing to my address in the tracking center are from internal people.

 

I thought it was a DNS issue right at the start, I'll get back onto our ISP and see what they say.

[OutToLunch]

Is your webmail hosted on a different server to your actual mail server?

 

The link that you posted to webmail.thorntongrammar.bradford.sch.uk resolves to 195.188.173.17

 

The domain used in your email address is different - thorntongs.ngfl.ac.uk and has mx records which point to

 

mail.thorntongs.ngfl.ac.uk - 195.188.173.10

mail2.thorntongs.ngfl.ac.uk - 195.188.173.10

 

Has something got mixed up somewhere along the line?

[mrforgetful]

Both reside on the same server.

 

I believe those IPs are mapped (or maybe were when it worked and aren't now) through from the ISP to our PIX which will route each to the mail server.

 

The webmail.thorntongrammar.bradford.sch.uk is a new mapping which purely maps through to enable webmail access.

 

The mail and mail2, I'm really not sure as they're old ones so don't want to mess them up, but maybe they are already.

 

Unfortunately I don't have anything to do with the routing of traffic, the ISP do it up to the PIX and then our old Network Support company do the PIX to wherever because I don't know PIX stuff.

 

We have been having DNS issues with the Internet about the same time email broke though, so I guess I shall chase that and mention all this, I know from meetings that DNS is a massive headache for them for some reason.

[mrforgetful]

I'm pretty certain it's an external problem now.

 

Our school is in a bubble with some other schools and as such require seperate DNS setups for within that bubble and the Internet side.

 

I can receive email from a school within that bubble, but not addresses that are outside it.

 

Apparantly other schools in the bubble are experiencing email problems of differeing DNS problems, ie one can send and receive from external just fine but not from within the bubble.

Also the ISP were making DNS changes last week.

 

Unfortunately it has been known that to resolve DNS issues within the bubble one of the other school's IT guys has had to talk the ISP through the setup. That's me inspired with confidence, but at least I can now tell the head it's not us.