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Same network, different subnet, some cannot see each other.

Last response: in Networking
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May 9, 2011 9:22:50 PM

I have a problem with computers not seeing each other on the network
Here is how my network is setup.

I have Comcast modem/router (10.1.10.1) - assigning local IP as follows:

Comp#1: 10.1.10.3 (windows xp)
Comp#2: 10.1.10.4 (windows 7)
Subnet: 255.255.255.252
gateway: 10.1.10.1 (externally IP: 173.160.85.70)

Comp#3: 173.16.85.69 (Static IP for Server for FTP, Website and workgroup file server)
Subnet: 255.255.255.252
gateway: 173.160.85.70

All 3 are on the same switch.
I orginally had computer #3 same subnet as other computer with LAN IP as 10.1.10.2 and I port forwarded port 21, and 80 to be able to see the FTP and website out side by ftp://173.160.85.70...but it didn't work and I could only access it internally. I tried changing the ports, but still didnt work. So I assigned computer #3 with separate static IP address/subnet I got from comcast (173.160.85.69) ...and then the website and FTP can be access outside via ftp://173.160.85.69.

But the problem is that Comp#1 (WinXP) cannot see computer #3 which has shared folders, but Comp#2 can Comp #3.

All computers have same workgroup name, file share enabled....I do not know what to do?

Do I have to buy a new router? maybe have every computer connect to the new router and assign the router with the static 173.xxx.xx.69 IP?

More about : network subnet

May 10, 2011 3:29:26 AM

Something like this

Comp 1/2: route -p add 173.16.85.69 mask 255.255.255.252 0.0.0.0 metric 10
Comp 3: route -p add 10.0.0.0 mask 255.0.0.0 0.0.0.0 metric 10

It's been a really long time since I did this in school.. hope it works, let me know.
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May 10, 2011 10:37:32 PM

sparktree said:

I orginally had computer #3 same subnet as other computer with LAN IP as 10.1.10.2 and I port forwarded port 21, and 80 to be able to see the FTP and website out side by ftp://173.160.85.70...but it didn't work and I could only access it internally.

That is what a DMZ is for. It is like port forwarding, but more reliable.
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May 22, 2011 6:31:14 AM

I tried DMZ as well, but it didn't work.

After talking with my ISP several time with different customer agents, many of whom were not very knowledgable, I found out that DMZ and portwarding will not work. The modem/router provided by the ISP will not directly forward it and so you cannot use the gateway WAN IP, and you simply had to assign the server with static IP I purchased...which is why it worked when I assigned the server as 173.160.85.69.

After figuring this out... I researched around the net for a best way so that the server, which now has separate static IP (173.160.85.69) assigned by ISP, can be accessed by other computers on the same phyical router, but assigned different gateway, and subnet, so on a different network. I found some people used another router or using 2 NIC cards, etc and somehow got it too work. At the end, the solution I adopted was assigning two set of IP's, gateway, Subnet for the server. I assigned 10.1.10.2 internal IP with 255.255.255.252 subnet, and 10.1.10.1 gateway....and I assigned another IP as the static IP I purchased 173.160.85.69. With this, all the computers can see each other. Only annoying fact is that when you click on network, you see the server computer twice....only on Windows 7. Windows XP sees only one computer via internal IP assigned to the server. But on the windows 7, it sees server on both the internal IP and the serparate WAN IP, showing same server twice. I guess this is because windows 7 is a bit smarter, so even when I didn't assigned separate internal IP, it somehow can still find the computer which has different direct WAN IP and thus a different network, but because it is on the phyiscal router, it can find it.

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