Solved

Open Port 25 through ADSL Modem and Router

Posted on 2006-11-11
13
1,386 Views
Last Modified: 2011-09-20
I want to setup an Exchange Server bhind my ISP's ADSL Modem and a LinkSys Router, but I am unable to see port 25 when I go to canyouseeme,com and check the port.  I haved contacted the ISP, they say I cannot make changes to their modem, and I have disabled the Firewall on the Router.  Any help is appreciated.
0
Comment
Question by:cperez59
  • 4
  • 4
  • 2
  • +1
13 Comments
 
LVL 104

Expert Comment

by:Sembee
Comment Utility
I would ask the ISP if they are blocking port 25.
With most routers, it isn't just removing the firewall features, but you have to setup the port redirection as well. Therefore make sure that is correct first.

Simon.
0
 

Author Comment

by:cperez59
Comment Utility
Simon,

I've called the ISP numerious times and of course they insist that they are not Blocking Port 25 - as I am recieving email to Outlook?  (Which I think is different?)  

At any rate - I just attempted to connect directly to my ADSL Modem and then went to canyouseeme.org and I'm still getting a "Connection Timed Out" message.

The ADSL Modem did have a Port Triggering Page and I did add:
mail 25 to 25 IP 25 to 25

Help
0
 
LVL 104

Expert Comment

by:Sembee
Comment Utility
Receiving email in Outlook is different as Outlook pulls email from the ISPs server via POP3.

I don't have access to a Linksys router at the moment, but from memory you have to setup the port to be opened and the forwarding separately. You need to ensure that you are forwarding the traffic to the internal IP address of the Exchange server.

Services like the one you are using will not see a port if there is nothing listening on the other end. Therefore the first place that you always have to look at is the router/firewall to see if it is blocking the traffic. Disabling the firewall functionality is not enough as that just exposes everything. As you will be using NAT to share the single external IP address, you need to configure forwarding.

If you have been playing around with the router for some time then I would hard reset it so that it is back to the defaults. Then attempt to configure it again for just port 25 being forwarded to the Exchange server.

You should also confirm that the Exchange server is listening on port 25.
On a workstation, drop in to a command prompt and type

telnet ip.ad.re.ss 25

where ip.ad.re.ss is the actual INTERNAL IP address of the Exchange server. You should get an SMTP banner back with the servername and the date and time. If the cursor just sits there then either you aren't using the correct IP address or something internal is blocking the port. Some AV software has this feature - Symantec and McAfee spring to mind.

Simon.
0
 

Author Comment

by:cperez59
Comment Utility
Simon,

Correct me if I'm starting in the wrong place -

STEP 1. From inside the Network ... Telnet 192.168.x.x  25
Returned:
220 pezfam.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.211 ready at  Sat, 11 Nov 2006 18:19:22 -0500

Therefore I'm assuming that the Exchange Server is listening.

STEP 2: Connect to the Router, and check the Port Forwarding and Port Triggering

Note:  I did disconnect my computer from the Router and plugged it directly into the DSL Modem and went to canyouseeme.og and trried Port 25 - it returned "Connection Timed Out"

Chris



0
 
LVL 104

Expert Comment

by:Sembee
Comment Utility
The first test is what was to be expected.
The second test, presuming that you are trying to use the correct IP address and the Exchange server can see out would tend to indicate that port 25 is indeed blocked.

You could test this by changing the port to 2525 (for example) on the SMTP virtual server then testing that. If that works, then port 25 is blocked. If that doesn't work then you have another problem.

Simon.
0
Want to promote your upcoming event?

Is your company attending an event or exhibiting at a trade show soon? Are you speaking at a conference? Spread the word by using a promotional banner in your email signature. This will ensure your organization’s most important contacts are in the know.

 
LVL 18

Accepted Solution

by:
carl_legere earned 250 total points
Comment Utility
is your linksys getting a real ip address?  Give us it the first three numbers eg: 24.25.26.xxx

Many ISP's now send you DSL modems with build in NAT firewall / router turned on.  This is a big problem for users who desire to put thier (easier to configure) router behind the DSL modem.  A NAT firewall behind a NAT firewall will work ok for web browsing, but is unreliable for inbound requests.

What modem is it?   You have to look up how to make the modem a bridge mode.

If you are on PPPoE or PPPoA you will need for the Linksys to do the authentication after changing the modem to a bridge.

Ok i just looked up your domain, and you are not on static service.  Running a mail server on dynamic can be very flakey.  Like Simon said it is likely that the ISP is going to block port 25.  XO is one of those mega providers that likes to do that.

If you get stuck, then you may consider not using the linksys and just progamming the ISP router as needed.
0
 

Author Comment

by:cperez59
Comment Utility
Simon,

Correction to my earlier entry.  I re-connected the ADSL Modem directly to the server and was able to connect to the Internet, Send an Email to my Hotmail Account and reply back to my Exchange Server.

Settings / Changes:
DSL Modem: Open Virtual Server (Port Forwarding) to the IP Address of my Server
DSL IP 192.168.1.x  Server IP 192.168.1.xx

Changed the IP Setting per the Server to:
IP Address: 192.168.1.xxx
Gateway: 192.168.1.x (the same IP as the DSL Modem)
And Pointed DNS and WINS back to the server itself?

At any rate this worked.

However, as soon as I attempt to put either the LinkSYS Router or a LinkSYS Switch between the Modem and the Server - it fails to forward Port 25???

Chris
0
 
LVL 104

Assisted Solution

by:Sembee
Sembee earned 250 total points
Comment Utility
If the IP address that you are getting from the modem is 192.168.x.x then they are natting. You need to follow the advice from Carl above to see if you can get the device changed to deliver the real IP address to your router.

Double NATing, which is what will be happening in the current configuration will cause you problems. If the ISP refuses to change the configuration of their modem then you will have to buy your own, or buy a device which is a combined modem/router.

Furthermore, if the ISPs device is giving you an IP address of 192.168.1.x then that will be clashing with the default IP address used by your router. You would need to change the subnet used internally to something like 192.168.11.x (ie anything but 192.168.1.x).

You may also be better off posting this question in the networking topic area, as I don't think it is a problem with Exchange, but your network hardware.

Simon.
0
 

Author Comment

by:cperez59
Comment Utility
Simon,

Thanks for the information!!

Do you think I should just start over and install a second NIC in the SBS 2003?

The external NIC will be connected directly to the DSL Modem
The internal NIC will be connected to a dumb switch.

Will that avoid the problem that I'm having pertaining to the NAT?

Chris
0
 
LVL 18

Expert Comment

by:carl_legere
Comment Utility
Why add a second nic?  The basic NAT firewall in the DSL modem provides a reasonable protection.  Although windows can be used as a router, it is usually only done for specific reasons that would make your scenario not 'typical' which makes it hard to troubleshoot forever.

Even though your ISP does not want you messing with the router, if you can administer it, then get a good manual and either find out how to disable the firewall and try bridgeing OR use the DSL modem as your firewall, or upgrade your service to STATIC IP for business, and they will be more helpful in supporting this.
0
 
LVL 39

Expert Comment

by:redseatechnologies
Comment Utility
Linked issue for more information -> http:/Q_22054111.html
0

Featured Post

Free book by J.Peter Bruzzese, Microsoft MVP

Are you using Office 365? Trying to set up email signatures but you’re struggling with transport rules and connectors? Let renowned Microsoft MVP J.Peter Bruzzese show you how in this exclusive e-book on Office 365 email signatures. Better yet, it’s free!

Join & Write a Comment

Resolve DNS query failed errors for Exchange
Resolve Outlook connectivity issues after moving mailbox to new Exchange 2016 server
In this video we show how to create an Accepted Domain in Exchange 2013. We show this process by using the Exchange Admin Center. Log into Exchange Admin Center.: First we need to log into the Exchange Admin Center. Navigate to the Mail Flow >> Ac…
The video tutorial explains the basics of the Exchange server Database Availability groups. The components of this video include: 1. Automatic Failover 2. Failover Clustering 3. Active Manager

763 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now