switch, subnet and direct path

[lamplighter]

I have a home network with 3 computers and 3 IPs from @Home assigned dynamically. Each computer has 1 NIC card, and each goes to my 3Com OfficeConnect 8-port Switch. Two computers are Win2k and the third is Linux.

The 2 Win2k computers are already sharing files fine and stuff using NetBEUI. The problem comes in with the Linux one (I know this isn't a Linux place, but I am trying to keep the question about the networking aspect here =). I simply want to be able to transfer through FTP from Win2k to Linux, and for it to take the direct route (Win2k -> switch -> Linux). However, it goes through the net (Win2k -> switch -> cable modem -> switch -> Linux), meaning it goes at 25 k/s. I think it must be because of the subnets. The 2 Win2k IPs are 24.xx.140.xx while the Linux IP is 24.xx.97.xx. I tried FTPing from Win2k to Win2k and it transferred at instead of 500 k/s, like it should, and a tracert seemed to verify these findings.

Does this make sense, that the reason the switch does not recognize the direct path is the subnet? After I get that verified, does anyone know if there is any way to make the switch recognize that 97 as the same subnet as 140, or force it to take the direct path? Or is assigning internal IPs the only other option?

Thanks for any help.

 

[Russ]

<< Does this make sense, that the reason the switch does not recognize the direct path is the subnet? >>



Logically, that makes sense to me. I have a direct path from my Windows machines to my Linux box here, but that's because I put two NICs in the one that serves both inside and outside.

I also have virtual IP addresses assigned to one of the NICs. Can you try this? Not sure if it would work since your WAN addresses are dynamic.

But, if you can do it, it would seem that you could just create an Eth0:1 on the NIC in the Linux box and assign it an address from the same subnet as the addresses being assigned to the Windows machines.

Russ, NCNE

 

[spidey07]

IP is working as designed. The linux box realizes that the 24.xx.140.xx host is not on the local subnet and sends it to the default gateway (cable modem)

What you have there is called multinetting - running different logical networks on the same physical network. This practice is HIGHLY discouraged because of just what you described.

Now, with all that being said maybe RUSS's solution will work. Another alternative is to buy one of the SOHO routers from netgear, linksys, SMC and run RFC1918 private addressing (192.168.x.x, 10.x.x.x, 172.31.x.x).

Or maybe see if you can get @home to set you up a reservation on DHCP to make sure you get address from the same IP network.

hope this helps!

 

[ScottMac]

Actually, since the 24.0.0.0 network is a class A, even through the thrid octet is a different number, they could still be on the same subnet. It's all going to depend on what you subnet mask is. You probably have an improper subnet mask, probably on the LINUX box. You may have omitted an octet or more likely, added one, or made one a &quot;255&quot; that should have been a &quot;128&quot; or typo'd, but it almost HAS to be an improper mask.

It's HIGHLY unlikely that they are running several subnets through the same cable feed to one location.

Check your settings (on the LINUX box probably) against the provisioning information from your ISP/Cable/DSL folks. Call 'em or check their web site to verify your provisioning info.

Good Luck

Scott

 

[lamplighter]

Hehe, I can see why multinetting is highly discouraged =)

I will have to look into that suggestion Russ, thanks. I was considering making a Direct Cable Connection with the parallel ports (and a null modem piece).

I have a feeling the reason the Linux computer's IP address is so different is because when I filled out the info for a new IP, one of the things to choose is OS. I chose Linux, and Win2k for the others. Maybe if I simply delete that IP and request a new one with Win2k it would work?

When I type ipconfig in Win2k, my Subnet Mask is 255.255.255.0, and ifconfig in Linux says &quot;Mask: 255.255.255.0&quot;. It appears the &quot;Mask&quot; is actually the Netmask... do I still need to figure out what the subnet mask is or is netmask the same thing?

And thanks for all the responses, I couldn't believe it when I checked back in an hour and got 3 excellent replies 🙂

 

[CTR]

I think Russ' suggestion was a good workaround here, but in my opinion you should use private addresses. As long as you're multinetting add a 192.168.1.x address to your linux ethernet interface, and one to your win2k ethernet interface. Then they can communicate with each other using the private addresses. Sound like a good idea?

 

[lamplighter]

Yes, that does sound like a good idea 🙂 Then I am not relying on @home, or don't have to buy anything. Just gotta figure out how to do that in Linux, though.