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cli7554Flag for Canada

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IIS Port Forwarding

Hi Experts, ok, here is the situation.  With ISPs shutting down Port 25, my little Domino mail server is going to be harder to access if I leave my house (which happens frequently).  I have checked, and Domino cannot listen to two ports at the same time for incoming mail (if it could, I would open port 25 and 587 and life would be good).  So I asked a couple people and they suggested something that would basically do a port relay.  In other words, it would listen to port 587 and send anything that comes through over to port 25 (where my server could pick it up and send it/deliver it appropriately).  I did some searching a found one program that would likely work, but is $200 (I would like to keep the cost minimal - ie, free).  I was also told that IIS is capable of doing this task, but I have no clue how to set it up to do so.  So... my challenge to you guys: is there a good, free port forwarding application out there, or how would I go about setting up IIS (Server 2003 Standard running Domino, which I don't think will affect anything) to listen on port X and forward/relay to port Y of localhost?
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msguru

Why not do the port translation on the router?  A Cisco router should be able to do it, also I have done port forwarding on draytek DSL routers.  Any decent router should have port forwarding functionality - check out your one!

Best of luck!
Avatar of cli7554

ASKER

Unfortunately, since this is a home mail server, it is just running behind a standard Linksys wireless router.  It does not have the capability to forward beyond opening Port 25 -> 192.168.4.34 (or whatever IP).  But thanks for the suggestion... keep 'em coming...

btw, I am on cable, not DSL
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This service says it can deliver mail to an alternate port:
http://www.dyndns.com/services/mailhop/relay.html

They charge about $40 a year, but you get other benefits like spam filtering and "store and forward" which would give you better resilience if your server was down for a short time.

You would have to open the alternate port on your Linksys and set your mail server to listen on that port.

This seems to do it:-
c:\>netsh
netsh>interface portproxy
netsh interface portproxy>add v4tov4 listenport=587 connectaddress=192.168.0.100 connectport=25 protocol=tcp

See:-
http://technet2.microsoft.com/WindowsServer/en/library/2e145188-ce7e-4556-8540-abd9e7feb46c1033.mspx?mfr=true
http://support.microsoft.com/kb/555744
Even if you are able to translate port 587 to port 25 at the firewall - or on the local mail server - that alone will not solve the problem because incoming mail from the Internet will only arrive on port 25. Remote mail servers will not know to send you mail on port 587. That is why you need an externally hosted service such as the dyndns.org relay service. It receives the mail on port 25 and re-delivers it to port 587.

The MX records for your mail domain will have to be changed so they point to the mail relay service, but there are instructions on what is required on the link I posted before.

Your Domino mail server should then only need to listen on one port unless it is receiving mail from local servers on port 25. I don't know this product, but I'm sure it would still send outbound mail to port 25 on remote servers even if it has been set to listen on a different port.
Hi cli7554,
Further on what fetias said above, you mentioned:-
 "With ISPs shutting down Port 25, my little Domino mail server is going to be harder to access if I leave my house (which happens frequently)."
So, how do you connect to your Domino mail server when you're away from home?  Some sort of web access, or fat client (what ports does the fat client use)?
Avatar of cli7554

ASKER

Thanks Fetias for your comment, but again, I have no desire to go third-party if I don't have to.  Currently, if wherever I go is on cable, I access it normally (through Outlook setup with POP3 access) with no problems.  If I am somewhere with DSL, I usually just take remote control of my home workstation from my laptop and do things that way.  If neither of those work, I will simply use a different account.

msguru, I will give that a shot.  I haven't had a chance to look at it for the last couple of days, but hopefully today or tomorrow I will be able to get back to it.

Thanks for the suggestions!!
For the client access with Outlook, I presume sending e-mail is the issue when you're away from home - as that would be with SMTP (understanding your issue a bit better now, hopefully!).
Does the Domino mail server have a web access feature that you could set up - similar to Microsoft's Outlook Web Access (OWA) for Exchange?  That would solve the problem!
Avatar of cli7554

ASKER

Yes, it does, and if necessary I could do that, but as soon as I do, I lose all the contacts I have set-up in Outlook.  However, I also use multiple e-mail addresses on my laptop, and would like to use this server as the default out-going server for them when they can't send either.

If I am not able to set up the port-forwarding, I can certainly work around it, it would just be a nice solution to the problem.
I use MS Exchange 2003 using the HTTP connectivity setup - this lets you use the full Outlook client anywhere on the Internet, so that I can have the full features of Outlook with multiple mailboxes, multiple e-mail addresses, etc, etc.
Not trying to convert you to MS... but that's what I use, and it works very well!
Let us know if the port forwarding works, anyway.
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ASKER

Will do, and thanks for the assistance.  
Avatar of cli7554

ASKER

I got it working!  Turns out if you configure the properties of the SMTP server within IIS to listen on port 587, then send out on port 25.  You set up the smarthost to send all incoming messages to localhost (basically it routes to itself, but on the different port), and open up the relaying.  I do realize that this creates an open relay of sorts, but since the only place it can send messages to is my Domino server (which has its own spam filtering, I use both DNS blacklisting and IP filtering) I am not concerned with anyone using me as an open relay.  

Thanks for all the suggestions though, I do appreciate them!
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Computer101
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