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(Full disclosure: I rate barely above "noob" when it comes to networking.) My workplace recent got a new web server. Since we're nearing the end of an overhaul of our website, we're doing a slooooow migration between the old web server and the new one.

The old webserver (we'll call it SERVOLD) is Windows Server 2008 with IIS 7. It does not have SQL Server installed. The new server (SERVNEW) is Windows Server 2008 R2, IIS 7.5, with the same version of SQL Server installed. Both are located in the DMZ for our network, and both have their own outward-facing IP address (.3 and .4, respectively).

Each server can communicate fine with computers within the domain (not in the DMZ), and those same computers have no trouble communicating with either server. Both servers are also accessible from the internet just fine. However, no matter what, these two servers just refuse to recognize each other. They have the same Workgroup name listed (WORKGROUP), and I thought that would be enough for them to recognize each other.

What needs to happen such that I can get these two servers to communicate with each other? We want to do a gradual roll-over to the new website (new one uses ASP.NET, old one uses CFMX), so being able to use one database between both servers is a necessity.

Thanks!

Updated Information

To be more precise, when I say they "can't communicate", I mean they can't do anything with regards to each other. No file sharing, no SQL communication. As mentioned, both have outward facing IPs, and I can't even access their respective sites within the browser.

When I try to access a shared folder, I get error code 0x80004005 (Unspecified error) (not that helpful).

When I try to ping, I time out. However, if I do ping [servername], it does attempt to ping the correct IP address.

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Explain what you mean when you say that they can't communicate. They can't ping each other? You can't connect to the web site on one from the other? You can't connect to SQL Server on one from the other? Saying that they can't communicate with each other is like saying that my car doesn't work and asking you to diagnose it for me. –  joeqwerty Nov 24 '12 at 3:00
    
Sorry, I should have explained further. When I mean "no communication", I mean they can't do a single thing with regards to each other. One might as well be in different dimensions as far as the other is concerned. No SQL connection, no file sharing, no ping. Both have a static, internet-facing IP (starting 172.). I can successfully ping both from within my network. –  Tukaro Nov 26 '12 at 17:17
    
I should add that if I do "ping [servername]", it does try to ping the correct IP address. A firewall issue, perhaps? –  Tukaro Nov 26 '12 at 17:24
    
That's just your DNS properly resolving the name before it pings it. –  Safado Nov 26 '12 at 18:03
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Some information that would help: How are the NICs configured (i.e. netmask) and what's the topology of the dmz (do they each connect to a switch and then to the firewall, or are they both directly connected to the firewall), have you tried running wireshark on each server to watch the traffic coming in and going out as your testing? Have you tried disabling windows firewall temporarily to see if it's the problem? –  Safado Nov 26 '12 at 18:17
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1 Answer

up vote 1 down vote accepted

Problem resolved. The two servers had static IP and DNS configurations, but the Subnet mask was different. First (old) server had 255.255.255.0, second (new) server had 255.255.255.255. Probably an oversight by the guy that did the initial server setup and installation before handing it over to us.

As soon as I changed the new server to use the same mask as the old one, everything worked dandy.

Special thanks to Safado for their assistance, which led to the resolution.

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