I've just installed two RH6.1 stations on an NT network. Their IP addresses are DHCP-assigned at boot OK, but then I can't get them to see each other unless I check what address has been assigned to each, after which I can at least get them to ping each other. That's about it. They don't seem to know their Hostnames anymore, so when I export a directory, the importing machine can't find the host that's supposed to be exporting. I've done these things pretty easily with fixed IP addresses before, but have no experience with DHCP. Can anyone point me in the right direction? <p>Charles Nardino<br><a href=mailto:cnardino@bellatlantic.net>cnardino@bellatlantic.net</a><br><a href= > </a><br>
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NFS Export/Mount with DHCP
- Thread starter cnardin
- Start date
Use fixed IP addresses for your servers - might not be the only solution to the problem, but IMHO, the best.<br>
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You should always know where your servers are. Assigning the IP addresses to a server using DHCP looks good in practice, but what happens if your DHCP server goes down? You can't reboot the servers, because they'll never get an IP address. What happens if your naming service goes down, and you've lost connection to one of the servers? (eg, DNS) Which IP address are you going to ping to make sure the server is back up?<br>
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As to not knowing their hostnames, hostnames are simply mappings from IP addresses to human readable names using either a text database (/etc/hosts) or something else (DNS).<br>
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As the IP address of your servers is going to (potentially) be changing <i>every time</i> you reboot the server, it's very difficult to set up mappings of names to addresses... There is a way of integrating DNS with DHCP. However, for the previously mentioned reasons, I'm not going to go down that path, because I think it's a dark and dangerous one to tread...<br>
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So, to sum up, give your servers static IP addresses. Let DHCP handle assigning IP addresses to workstations, which is really what it was designed for, not servers.<br>
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HTH.
<br>
You should always know where your servers are. Assigning the IP addresses to a server using DHCP looks good in practice, but what happens if your DHCP server goes down? You can't reboot the servers, because they'll never get an IP address. What happens if your naming service goes down, and you've lost connection to one of the servers? (eg, DNS) Which IP address are you going to ping to make sure the server is back up?<br>
<br>
As to not knowing their hostnames, hostnames are simply mappings from IP addresses to human readable names using either a text database (/etc/hosts) or something else (DNS).<br>
<br>
As the IP address of your servers is going to (potentially) be changing <i>every time</i> you reboot the server, it's very difficult to set up mappings of names to addresses... There is a way of integrating DNS with DHCP. However, for the previously mentioned reasons, I'm not going to go down that path, because I think it's a dark and dangerous one to tread...<br>
<br>
So, to sum up, give your servers static IP addresses. Let DHCP handle assigning IP addresses to workstations, which is really what it was designed for, not servers.<br>
<br>
HTH.
- Thread starter
- #3
Thank you for your help, AnydBo. My experience is pretty limited, especially when it comes to mixing with NT servers. Let me add some of the details. We have 4 NT servers serving about 300 Win95 stations. We just set up these 2 Linux stations to experiment with. I originally assigned class C addresses to them and they had no trouble seeing each other, but they couldn't see the rest of the network, including our T1 Internet gateway. If I accept the DHCP addresses, we can then use the gateway, but the 2 Linux stations no longer have access to each other. We'll be trying to set up Samba soon, but there too, my experience so far has been with 10 stations or fewer -- simple peer networks where I've set up a Linux file server, all with fixed IP addresses. The NT guys aren't much help with Linux set-ups. <p>Charles Nardino<br><a href=mailto:cnardino@bellatlantic.net>cnardino@bellatlantic.net</a><br><a href= > </a><br>
Typical of the NT guys! ;^)<br>
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The basic principle of my previous post is going to stay the same. Assign static IP addresses to the Linux boxes. Don't let them use DHCP for grabbing IP addresses. It's generally considered to be a "bad thing" for servers to do this...<br>
<br>
However, there is, I believe, a way to get the DHCP server to reserve certain IP addresses for certain servers. Whenever you switch on a workstation or server that gets IP details from DHCP, it sends out a "Give me an address" request. This request includes it's NIC MAC address. The DHCP admin should be able to map the MAC addresses to permanent IP addresses.<br>
<br>
Having said that, though, I still say stick to permanent IP addresses for the Linux boxes. That way, if the DHCP server goes down, your Linux servers aren't affected.<br>
<br>
You say that when you assigned class C addresses to the Linux boxes they could see each other but not the rest of the network. What were the IP addresses you assigned? Give an example IP address of a machine elsewhere on the network that needs to contact the Linux box (or vice versa). Did you set up any routing on the Linux boxes? When you accept the DHCP addresses, what addresses do you get?<br>
<br>
A few questions there to keep you going
Let me know, and I'll see what I can do to help you out
<br>
The basic principle of my previous post is going to stay the same. Assign static IP addresses to the Linux boxes. Don't let them use DHCP for grabbing IP addresses. It's generally considered to be a "bad thing" for servers to do this...<br>
<br>
However, there is, I believe, a way to get the DHCP server to reserve certain IP addresses for certain servers. Whenever you switch on a workstation or server that gets IP details from DHCP, it sends out a "Give me an address" request. This request includes it's NIC MAC address. The DHCP admin should be able to map the MAC addresses to permanent IP addresses.<br>
<br>
Having said that, though, I still say stick to permanent IP addresses for the Linux boxes. That way, if the DHCP server goes down, your Linux servers aren't affected.<br>
<br>
You say that when you assigned class C addresses to the Linux boxes they could see each other but not the rest of the network. What were the IP addresses you assigned? Give an example IP address of a machine elsewhere on the network that needs to contact the Linux box (or vice versa). Did you set up any routing on the Linux boxes? When you accept the DHCP addresses, what addresses do you get?<br>
<br>
A few questions there to keep you going
Let me know, and I'll see what I can do to help you out - Thread starter
- #5
Thanks again for your help, AndyBo. I had just checked out some of the very things you suggested and am now really confused. Our two Linux machines are getting addresses in the range 10.10.*.*, but nearby Win95 machines are 248.*.*.*. We were told we should use our ISP as our domain (connect-something.com - I'm not in the office, so I can't get details now), but the NT "domain" is "Education". I don't know what to make of NT domains anyway. The gateway we're using is that of our ISP. That's one thing that works, but only if we accept DHCP addresses. The fixed addresses I had tried that worked only between the two Linux stations were 192.168.1.1 and 192.168.1.2. Using them cut us off from the Internet. I wish I knew more about the overall structure of the place. <p>Charles Nardino<br><a href=mailto:cnardino@bellatlantic.net>cnardino@bellatlantic.net</a><br><a href= > </a><br>
When using dhcp How do you resolve the other servers name??<br>
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I agree with AndyBo get real addresses for your isp not <br>
a reserved address like 10.* 192.168.* or that other one.<br>
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You can't mount anything you can't find ( you have to be able to resolve to an ip address )
<br>
I agree with AndyBo get real addresses for your isp not <br>
a reserved address like 10.* 192.168.* or that other one.<br>
<br>
You can't mount anything you can't find ( you have to be able to resolve to an ip address )
Sorry for no reply for a while - been unavoidably afk for a week or so...<br>
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Sounds like the address of the internet gateway is not a 192.168.*, 10.* or 248.* address. Therefrore, your Linux boxes won't be able to see the gateway, because it's not on the same network...<br>
<br>
You need to do one of two things:<br>
<br>
1) Get those permanent IP address for the Linux boxes that use the same network number as your gateway.<br>
<br>
2) Change the gateway router IP address to match the Linux boxes network number.<br>
<br>
I'd go for number 1 any time... HTH.
<br>
Sounds like the address of the internet gateway is not a 192.168.*, 10.* or 248.* address. Therefrore, your Linux boxes won't be able to see the gateway, because it's not on the same network...<br>
<br>
You need to do one of two things:<br>
<br>
1) Get those permanent IP address for the Linux boxes that use the same network number as your gateway.<br>
<br>
2) Change the gateway router IP address to match the Linux boxes network number.<br>
<br>
I'd go for number 1 any time... HTH.
A dhcp server can take the name of the two machines (hostnames) and the hardware address and give them the fixed ip address, it is easy to do but when fixing ip addresses you should give the machines a fixed ip address then make sure the dhcp server knows the fixed ip address your giving. then no other machine will get the ip address. if another machine gets a same ip address it will end up in a lot of conflict. <p>Simon Jones<br><a href=mailto:sijones_uk@yahoo.com>sijones_uk@yahoo.com</a><br><a href= Allandale Youth Works</a><br><b>God</b> am good!!! and good lookin
- Thread starter
- #9
Thanks to everyone for your suggestions. I'm afraid the outfit in question is too big to accomodate two little "Linux freaks" trying to "break into" their network. We've decided instead to "hog" just two stations for ourselves, with Linux on one of them and Win95 on the other, connect them directly via crossover cable and set up a mini-mini-Samba network of our own. Once we've worked everything out independently, we'll install a second NIC in the LInux box and connect to the corporate network using DHCP, then try to connect the Win95 station through the Linux station. It's not all we were hoping to accomplish and it's not going to prove anything much to anyone, but it's OK for starters at least. When people see that we can get this to work, then maybe they'll let us try something on a larger, more complicated scale. Thanks again. <p>Charles Nardino<br><a href=mailto:cnardino@bellatlantic.net>cnardino@bellatlantic.net</a><br><a href= > </a><br>
Good Luck! Don't forget that it's going to be network routing that's the all important issue when it's time to plug back into Corporatesville. That Linux box is going to be working as a gateway, and you'd need to tune the kernel accordingly. (Start with IP Forwarding and work up from there.)<br>
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Hope all goes well!
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Hope all goes well!
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