File Server, invisible to internet

Mallow005 · n00b Joined: 15 Nov 2002 Posts: 49 Location: CA

Hello-

Ok, well I know it's possible. I'm in college right now and each room has a cable modem/router. My suitemate decided to put up a fileserver just for our suite. So he connected a switch to each router in our rooms using crossover cables. Then he connected the server to the switch. The server was running Red Hat. We configured the server to use the IP 128.54.254.255, the rest of the computers were 128.54.140.x. Same subnet mask. Not sure what the broadcast was, but I don't think it's very important. Well, it works. Setup Samba and there you go, file server just for our suite and was invisible to the net and couldn't reach the net itself.

But then we installed Gentoo. We put the exact same settings into the /etc/conf.d/net file and made sure eth0 was up and using the settings, yet we couldn't ping anything at all. This is straight off a base gentoo install with only vim emerged. Is there anything else we have to emerge for this to work? When we set it to use dhcp then it works just fine, the only problem is that it's visible to the internet and it goes through the universities intranet to access other computers, even computers in the room next door. This is a problem because our intranet is very congested and we would like to utilize the switch's... switching abilities and the 100Mb ethernet card on the server to give us full speed per router to the server. Any ideas?

Gav · n00b Joined: 10 Oct 2002 Posts: 65 Location: Surrey, UK

I'm by no means an expert, but there are a few things that spring to mind.

The setting of a gateway
The setting of DHCP

I'd think that if you don't want this server to be visiable or to see outside your room then you don't need a dynamic IP or any gateway defined for it.

I'm not familiar with the way your network is setup (never had a network into my room at uni!). So what is giving out the IP's in your suite? If every room has a cable modem and a seperate router, are they all setup to NAT and DCHP? If so and they're all then connected by a switch, you should only have 1 DHCP running for the whole suite. Leave the server with a fixed IP (ie 192.168.1.1) and allow enough IP's for DHCP to more than cover everyone else (or tell everyone to do static IP - harder).

BTW, I have a post from a few weeks ago asking about changing from DHCP to static IP - How do I go from DHCP to static IP?

fyerk · Posted: Fri Nov 15, 2002 6:07 pm Post subject:

I'd use a different IP than 128.54.254.255 as x.x.x.255 is typically reserved for a broadcast address.
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Mallow005 · n00b Joined: 15 Nov 2002 Posts: 49 Location: CA

we tried differnt IPs too, such as 128.54.254.254, 128.54.140.90, etc. Yes I know what to set for the gateway and DHCP, we just turned DHCP on as a test to see if the card/network was working.

Every room has a cable modem/router. As in, a cable modem and router in one. Yes theoretically we should be able to pick any free IP within the 128.54.xxx.xxx range and it should see each other, yet it doesn't. Same subnet mask.

rac · Posted: Fri Nov 15, 2002 11:49 pm Post subject:

Is there a reason you're not using RFC 1918 private IP address ranges?
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Mallow005 · n00b Joined: 15 Nov 2002 Posts: 49 Location: CA

I wish I knew what that meant. If you mean why aren't we using 192.168.xxx.xxx, it's because the rest of the computers in the suite have to use DHCP (well, we don't HAVE to, but I think that messes with the server). I understand (after reading up on IP stuff) that the first two segments have to be the same on our file server in order for it to see the other computers on the local network. Since the subnet mask for our computers is 255.255.0.0, then that means we CAN use 128.54.254.255 right? While assigning broadcast as 128.54.255.255

rac · Posted: Sat Nov 16, 2002 12:41 am Post subject:

Mallow005 · n00b Joined: 15 Nov 2002 Posts: 49 Location: CA

wow, multihoming overlay? that went straight over my head. I can infer what it means though, how would we do this with windows machines? As is the case with most of our suite. What I don't understand, is that we used the same IP and subnet before and it worked. I just put the exact same settings on my laptop, which is running gentoo as well, and it worked fine! Exactly how I wanted it to. I went over to the file server, put in the exact same settings, restarted eth0, and no dice, can't even see the broadcast. I have no idea why it would do this, it literally can't see anything else other than itself.