DHCRELAY setup

metallica1973 · 02-25-2008, 05:58 PM

Here is the network:

PHP Code:



Router/Firewall/DHCP/SERVER(eth1-192.168.3.1)
  +
  +
  +
Catalyst 2924
  +
  +
  +
RADIUS/SAMBA/Server/DHCRELAY
  +
  +
  +
Wireless Clients(192,168.3.0/27)

How would I setup a dhcrelay on the server?

PHP Code:



dhcrelay -d -i eth0 -m 192.168.3.1

It doesnt work!

acid_kewpie · 02-26-2008, 11:03 AM

well you only have one network there... what network do you want to relay for? the -m command requires an option too, so not suprising it didn't work.

metallica1973 · 02-26-2008, 12:21 PM

Acid_keypie to the rescue. This is the situation:

PHP Code:



router/firewall/dhcp server 
       eth1.3/VLAN3-192.168.3.1 
          + 
          + 
          +                  (AP - 192.168.3.5) 
   Cisco Catalyst 2924 + + + Cisco Aironet 1200 ++++++++ Wireless Clients 
          + 
          + 
          + 
       freeRADIUS server

This was working before until the power cut off in the office. When my wireless clients are authenticated by the RADIUS server they are unable to obtain an ip address from the router/firewall/dhcp server. I got it to work by adding dhcp to the radius server and having it assign ip's like:

PHP Code:



     router/firewall 
       eth1.3/VLAN3-192.168.3.1 
          + 
          + 
          +                  (AP - 192.168.3.5) 
   Cisco Catalyst 2924 + + + Cisco Aironet 1200 ++++++++ Wireless Clients 
          + 
          + 
          + 
   freeRADIUS/dhcp server

so for a better understanding, how would I have setup dhcrelay if I take out the dhcp server from the RADIUS box?

acid_kewpie · 02-26-2008, 01:16 PM

well you would use a dhcp relay if you have the dhcp server on a different network to that where you want to serve dhcp. the only network listed here is 192.168.3.0/27 from your diagram. if you are taking this /27 from the wider /24 then that's not going to play ball, as when the dhcp server on 3.0/24 then that's just going to look like a local request to that network. I've a feeling that you're possibly confusing notional informal assignment of address ranges with formal CIDR defined subnets... is this /27 actually "real" or just the desired ranges for wireless clients?

metallica1973 · 02-26-2008, 01:29 PM

PHP Code:



router/firewall/dhcp server 
       eth1.3/VLAN3-192.168.3.1/27 
          + 
          + 
          +                  (AP - 192.168.3.5/27) 
   Cisco Catalyst 2924 + + + Cisco Aironet 1200 ++++++++ Wireless Clients 
          + 
          + 
          + 
       freeRADIUS server

192.168.3.0/27 is the only subnet that I have.

acid_kewpie · 02-26-2008, 01:48 PM

ok, so there's nothing to need a relay as far as i can see. are you having trouble running the dhcp server on the linux box? tried wireshark (oh yes) on it to see if you get the DHCPDISCOVER messages?

metallica1973 · 02-26-2008, 02:10 PM

Wireshark to the rescue. It worked before and I have changed nothing on the server(dhcpd.conf) only on the catalyst 2924 to get the vlans working. Ever since that power outage the @#$!@$!#@ stopped working. Thats ok. I do have it working now. I just added dhcp to another box in VLAN 3 and it worked. So I will follow an old american adage " If it works dont @$%$@#% with it"