DHCP relay

Is it possible to use the LTM as a DHCP relay? In my setup I got one untagged VLAN (vlan269) on one physical interface. And about 10 tagged VLANs (NGP_*) on another physical interface. Since the LTM is running Linux I figured I could use "dhcrelay", see below:

 

 

big-ip dhcrelay -i NGPA_10_6_3_0 -i vlan269 -i NGPA_10_6_7_0 10.6.3.10

 

Internet Systems Consortium DHCP Relay Agent V3.0.1

 

Copyright 2004 Internet Systems Consortium.

 

All rights reserved.

 

For info, please visit http://www.isc.org/sw/dhcp/

 

Listening on LPF/NGPA_10_6_7_0/00:01:d7:6a:95:83

 

Sending on LPF/NGPA_10_6_7_0/00:01:d7:6a:95:83

 

Listening on LPF/vlan269/00:01:d7:6a:95:82

 

Sending on LPF/vlan269/00:01:d7:6a:95:82

 

Listening on LPF/NGPA_10_6_3_0/00:01:d7:6a:95:83

 

Sending on LPF/NGPA_10_6_3_0/00:01:d7:6a:95:83

 

Sending on Socket/fallback

 

 

 

Ok, looks good. The problem is that it doesn't seem to actually listen on those interfaces. I'm logging the traffic with a filter:

 

Jan 4 13:54:21 tmm tmm[930]: 01250002:5: test (86): accept on vlan 273, len: 342 [IPv4 328 0.0.0.0 -> 255.255.255.255 UDP 68 -> 67]

 

Jan 4 13:54:22 tmm tmm[930]: 01250002:5: test (87): accept on vlan 277, len: 590 [IPv4 576 0.0.0.0 -> 255.255.255.255 UDP 68 -> 67]

 

 

I also tried setting up a listening port with "nc":

 

big-ip nc -l -p 3000

 

 

host-on-client-vlan telnet 10.6.3.1 (big-ip floating IP or IP of master)

 

Trying 10.6.3.1...

 

telnet: connect to address 10.6.3.1: Connection refused

 

telnet: Unable to connect to remote host: Connection refused

 

 

Ok, that didn't work, try connecting to that port on localhost:

 

 

big-ip telnet localhost 3000

 

Trying 127.0.0.1...

 

Connected to localhost.

 

Escape character is '^]'.

 

 

Ok, that did work. Does this mean that it's not possible run services that listens on the VLAN interfaces?

 

Have I done something wrong or is there some other way to do it?

 

 

// Johan