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Old 04-10-2002, 10:02 PM   #1
Wood Cock
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Question DHCP on Linksys router


Hello ,

A repeat of the question I raised before. (I hit the enter key before I was finished - sorry). Here, briefly, is my problem: I have a Thinkpad T20 with a Xircom CE3 pcmcia card running Red Hat 7.2. I can do a dhcpcd on the machine from a normal DHCP server in one part of the university and I can also assgn a static IP address and get the interface up. HOWEVER, the dashed thing will not work when connected to a Linksys Router (BEFSR81). I tried to assign a static IP address and also tried dhcpcd and dhclient. None of these will get the interface up.

I understand that you can get a static IP with Linksys if you ask for a yyy between 2 and 99 in xxx.xxx.xxx.yyy. So I tried this:
#ifconfig eth0 192.168.1.xx up netmask 255.255.255.0
(x is a number between 2 and 99)
#route add default gw 192.168.1.1
Now ifconfig eth0 shows the correct setting. Yet the interface is not up as "ping <some IP>" shows. It tries for a while and then reports that the destination host in unreachable.

My next attempt was to install dhclient. dhclient eth0 does nothing! I cannot get an IP assigned. Nor will dhcpcd work.

All the three methods outlined work if I do not connect to the router. Let me also add that the router now provides networking for three comps : a FreeBSD one (dhclient), a Mac and a Win 98. So I know the router works. And I also know my comp (+Xircom) works when not connected to the router.

I would be immensely greatful for any help. Thanks.

Karthik
 
Old 04-10-2002, 10:23 PM   #2
mcleodnine
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Have you tried using the '-d' option when starting the dhcpcd daemon? This should give you extended information in your system logs and maybe a clue or two.

Just curious - are you plugging into the router itself? If the unit has a built-in hub, are you using the uplink port or the port right next to it? Same goes for any hub/switch.
 
Old 04-11-2002, 12:01 AM   #3
Wood Cock
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In reply to mcleodnine's questions, I am plugged directly into the router. I did try dhcpcd -d too. All known options (a rather vague term ! ) have been tried and I am frankly stumped. Help!
 
Old 04-11-2002, 12:44 AM   #4
mcleodnine
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Just to recap...

Your notebook works on your campus network.
Your notebook does not work on your BEFSR81.
Other computers connected to the BEFSR81 work.

My first guess is a cabling issue. Can you connect using another cable/port on the hub. (The hub is integrated with the router). I would try one of the cables from one of the functioning machines.

Otherwise the router may not be set up as a DHCP server. You may need to use a static IP. It depends on how the router was setup. Since my psychic abilities can only reach extraterrestrial beings and house cats I cannot determine the configuration of your router. That is up to you.

(PS - the neighbor's calico thinks that it has something to do with the hardware layer too. But he's an MCSE so I wouldn't trust his judgement.)
 
Old 04-11-2002, 05:09 AM   #5
Robert0380
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just to add to what mcleodnine said, make sure you have the router set up to act as a DHCP server. I too use a Linksys router, if its like mine (it should be similar) you can get to the setup page by going to http://192.168.1.1 and somewhere in there should be the part about DHCP.
 
Old 04-11-2002, 08:55 AM   #6
Wood Cock
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Chaps,

Thanks for the reply. Now the router is set up as a DHCP server (as I found from http://192.168.1.1 ). And I am ruling out the possiblity of the cable not working (The same notebook running Win 2000 can get the interface working. And before I deleted the FreeBSD partition, that too was able to connect to the router. I migrated from BSD to Linux and it remains a move I regret. There is no software support for IDL on BSD!). There is something exceedingly odd going on here and for the life of me I cannot figure out what it is. Superior brains to the rescue please!

Thanks,
KB
 
Old 04-11-2002, 09:20 AM   #7
hanzerik
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Re: DHCP on Linksys router

Quote:
Originally posted by Wood Cock

I understand that you can get a static IP with Linksys if you ask for a yyy between 2 and 99 in xxx.xxx.xxx.yyy. So I tried this:
#ifconfig eth0 192.168.1.xx up netmask 255.255.255.0
(x is a number between 2 and 99)
#route add default gw 192.168.1.1
Now ifconfig eth0 shows the correct setting. Yet the interface is not up as "ping <some IP>" shows. It tries for a while and then reports that the destination host in unreachable.
Try this:

Look at http://192.168.1.1 again and right down the dns server IP's it is using and right them down.
Or do ipconfig /all on windows machine connected to the router and right down the ip's.

Boot back into linux and do the steps you did above again, and add the dns server IP's in /etc/resolv.conf :
# Start /etc/resolv.conf
nameserver aaa.bbb.ccc.ddd
# End /etc/resolv.conf
 
Old 04-11-2002, 10:33 AM   #8
Wood Cock
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The rum thing is that I already have the correct entries in /etc/resolv.conf. I am proving to be difficult, am I not?
 
Old 04-11-2002, 12:16 PM   #9
hanzerik
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Try using netconfig, and start over and re-enter all info for a static connection. ie:
192.168.1.111 IP addy
255.255.255.0 NetMask
192.168.1.1 Gateway
xxx.xxx.xxx.xxx DSN ip's

once you are done ping the NIC: ping 192.168.1.111

Also take a look at the router while the computer is connected and booted up, is the lite for the port that your laptop blinking on/off/on/off. My router and hub both have had ports blown because of static electric shock(me sitting in my couch then standing up with my laptop in my hands), they wont work in 100mb they will only work at 10mb, I had to force the media type down from 100mb to 10mb and it works fine.
 
Old 04-12-2002, 08:53 AM   #10
johntmills
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Just to be thorough, have you cycled the router? I had an issue with mine that actually was on the ISP side. I know you situation isn't the same, but it's best just to rule it out. Try connecting the linux laptop to the router, and then hard reboot the router and reboot the laptop.

Hope that helps,

John Mills
 
Old 04-14-2002, 02:29 PM   #11
doris
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Does this symptom match yours?

You can ping any IP (in or outside LAN) but you can NOT telnet or ftp out.

If yes, it is very likely that you set an IP forwarding on your router and the target computer is not the problematic one.

TRY TO DISABLE IP FORWARDING!

This is because a port will be open to estabilish the network connection between your computer and the destination computer, but an improper IP forwarding will redirect the response to somewhere else. It appears that your machine is waiting forever, just like a DNS problem. Actually, the DNS is not reacheable too.

doris
 
  


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