topic Re: DHCP in Operating System - Linux

DHCP

Fred Martin_1 — Tue, 23 Sep 2003 10:26:23 GMT

Just set up Linux server on a PC - my home network. I have a Linksys router/switch which serves DHCP, so I configured Linux to use DHCP. I gave the linux box a hostname, checked the 'DHCP' option, and that was it.

My router assigns an address OK, but when I look at the router's DCHP client table, it shows the address of the Linux box, but not it's name.

Windows clients on my network -do- show the name in the router's DHCP client table.

So I must be missing something in the Linux config.

Re: DHCP

Fred Martin_1 — Tue, 23 Sep 2003 10:32:43 GMT

The question - what needs to be configured in Linux to have it register the hostname with DHCP, when it requests an address?

Re: DHCP

Alexander Chuzhoy — Tue, 23 Sep 2003 10:37:36 GMT

seems like your linux client doesn't update the dns itself. Look for the option in the router to do it for the client.
In windows there's a check box in DHCP configuration. In linux there's an option dynamic dns something.Look at the manual for your router.

Re: DHCP

Fred Martin_1 — Tue, 23 Sep 2003 12:29:32 GMT

I'm not running DNS specifically; DNS is coming from my ISP via the router. So I'm not sure that I understand what you mean. I don't see any settings on the router that apply (Linksys BEFSR11).

Since my Windows clients do pass their name on to the router, I figured it was a DHCP client-side setting someplace.

Re: DHCP

Steven E. Protter — Tue, 23 Sep 2003 12:54:15 GMT

The windows machines are probably making their names available to the router via netbios or WINS, not DNS.

This functionality is thankfully not available in Linux. If you are getting an IP address, DHCP is set up correctly.

ifconfig

Will display a matching address to the router table.

In this setup, the only way to get a hostname on that router table is to set up the router to hand out names at the same time as it hands out addresses. I'm not sure whether that router can do that.

That router does DNS as a default, forwarding information from your ISP.

I think in this case its situation normal, just not quite what you expected.

I would check that the hostname is set correct, though I don't believe it will help. I would do a dig and nslookup and make sure /etc/ressolv.conf is working(if you can browse you are okay). I don't think any of these steps will actually update that router table, but I've been wrong before.

SEP

Re: DHCP

Fred Martin_1 — Tue, 23 Sep 2003 13:21:46 GMT

Steven, I'm inclinded to think you are correct, esp. about the Windows thing. I've decided to contact Linksys tech support via email, they're responsive. I'll ask them about names.

Re: DHCP

Stuart Browne — Tue, 23 Sep 2003 19:18:18 GMT

If it is a NetBIOS thing (which I doubt), I can't see how it would work, given thatn NetBIOS needs an IP to work..

Windows has the irritating ability to send out names here and there. You could probably get the DHCP client on Linux to do the same thing with prompting.. I vaguely remember reading about it... gimmie a tick.

...

...

If you are using 'pump' for your dhcp client, it has a flag '--win-client-id' of which is listed in the help file as "Windows-like client identifier".

If you are using 'dhcpcd', uses the '-I' flag to specify a "Client ID".

To get these to work, you may need to modify the network startup routines. As you've not mentioned what distribution you are using, we can't give you too much help at this point.

Good luck! Let us know how you get on!

Re: DHCP

Fred Martin_1 — Wed, 24 Sep 2003 08:31:22 GMT

Thanks Stuart. I'm currently running RH6 but soon to install RH8. I did send an email to Linksys but alas, we're starting with 'is your router plugged in?' so it'll be a while. In any case, since it's OK for WIN clients I suspect now it's not the router and I will look at your suggestions.

Re: DHCP

Vitaly Karasik_1 — Thu, 25 Sep 2003 03:07:32 GMT

1) there is a bug in all RH 7.x, 8.0, 9 versions - DHCP client doesn't send its hostname.

in order to fix this, you need add

DHCP_HOSTNAME=your_hostname

to /etc/sysconfig/network

2) and if you want to update WINS from linux box, you can do this using Samba

Regards,
Vitaly