MX record DNS problem

[zagiace]

I inherited a network recently and I am trying to troubleshoot an issue that I am having.
My problem is that mobile devices when connected to WIFI will not connect to a local 2003 Exchange server. If a user were to try to send an email it fails. Take them off WIFI and the email sends.

I suspect that the reason is the local DNS server is not configured correctly. Sadly I am not well versed on setting up DNS and I could use a little help from the guru's.

The domain myweb.com is hosted off site. The mail server mail.myweb.com is hosted locally.

additional info, If I connect to the mailserver with OWA on a mobile device the mail goes through fine.

 

[kevnich2]

First to get more help, your going to need to post more info about your local setup. First off, what dns servers is your dcp server assigning for your network? Second, are those dns servers local or are they public dns servers. If they are local dns servers administered by you, what zones (website.com and company.local are both individual zones)?

 

[seepy83]

I'm not necessarily convinced this is a DNS problem. It sounds like your Wireless network just can't talk to the mail server. Assuming you're using outlook: ctrl+right-click the outlook tray icon and click "Connection Status...". Does it show you have established connections to your Exchange Server?

 

[zagiace]

Thanks to you both for the assistance,

First to get more help, your going to need to post more info about your local setup. First off, what dns servers is your dcp server assigning for your network? Second, are those dns servers local or are they public dns servers. If they are local dns servers administered by you, what zones (website.com and company.local are both individual zones)?

Thanks Kevnich2,
The DHCP server assigns the local IP of our DNS server then the IP of our internet provider. I verified this on my Note 3.
I will hopefully answer your next question correctly,
We have two Forward Lookup Zones
msdcs.MYWEB.local
MYWEB.local
We have one Reverse Lookup Zone
192.168.1.x Subnet

I don't see a root zone for a .com. Could that be an issue?

I'm not necessarily convinced this is a DNS problem. It sounds like your Wireless network just can't talk to the mail server. Assuming you're using outlook: ctrl+right-click the outlook tray icon and click "Connection Status...". Does it show you have established connections to your Exchange Server?

Thanks Seepy,
I don't have a laptop with outlook that connects to the mailserver. Just phones/tablets and a Mac. I will see if I can find one and connect it.

Here is a little more info. We also have a website hosted on our network.
Myweb.com is hosted off site
Myweb.net (our store) is hosted on another server on our local network. (I think we should probably have a dns record for this. am i correct?)
mail.myweb.com is our local mail server.

 

[RadiclDreamer]

Can you ping your email server? Can you telnet to the open ports?

 

[zagiace]

Can you ping your email server? Can you telnet to the open ports?

Thanks Dreamer,
On my wireless connection where I have the issue:
I can telnet to the local IP (192.168.1.XXX) of the mail server on port 25
I cannot telnet to the public IP (71.xx.xx.xx ) of the mail server on common ports.
I cannot telnet to the domain name (mail.myweb.com 25) of the mail server

I cannot ping the public IP (71.xx.xx.xx) I can ping the local IP(192.168.1.XXX)

 

[imagoon]

Thanks Dreamer,
On my wireless connection where I have the issue:
I can telnet to the local IP (192.168.1.XXX) of the mail server on port 25
I cannot telnet to the public IP (71.xx.xx.xx ) of the mail server on common ports.
I cannot telnet to the domain name (mail.myweb.com 25) of the mail server

I cannot ping the public IP (71.xx.xx.xx) I can ping the local IP(192.168.1.XXX)

Assuming all your addresses are correct, it sounds like a) the mail connector doesn't allow smtp connections from the 192.168.1.x (and it shouldn't really) and b) the router you have in place doesn't allow rubber banding the connections from inside -> out -> back inside. If you fix your router, then make sure the MX record points to the outside address, connections should establish then.

Why are the devices not using activesync?

 

[kevnich2]

Ah now that makes sense. From inside your local network, when you try and reaching mail.myweb.com it's getting it's IP from the DNS server as 71.x.x.x Your firewall likely doesn't allow loopback. You have two options: 1 - enable loopback in your firewall as a NAT rule so that if a system is trying to get to 71.x.x.x IP of your mail server on port 23 and whatever other ports you need that it translates that to the internal IP address of your mail server. ANother option is to add myweb.com as a zone in your local DNS server but make sure to create EVERY record that is in the public DNS in your local dns as well.

For example, if public DNS that hosts your myweb.com has several A records, a few cname records, some mx records, etc, all these need added to your internal DNS server so that they resolve correctly internally. The difference being that your mail host needs to point to the internal IP instead of what it's set to currently. My recommendation is do a loopback entry in firewall but yours may not have that as an option

 

[zagiace]

Thanks! I will give this a shot. I will not get to it until Monday but I will post back on my progress.