DHCP not working on 837.

Info on Cisco routers and bridges.

DHCP not working on 837.

Postby AM » Thu Dec 15, 2005 10:56 pm

I have an 837 (again!),

it seems that it doesn't provide IP addresses to clients.

I've got dozerns of routers where DHCP server worked but with this one (I tried 12.4(2)T2 and 12.3(11)YS1) I have a
statement "ip dhcp use vrf connected" and if I give "no ip dhcp use vrf connected" that strings is displayed anyway.
What is strange to me is that on the other routers I don't have that line both positive and negative.
Is that the source of my headaches?

Alex.
AM
 

Re: DHCP not working on 837.

Postby Guest » Fri Dec 16, 2005 10:50 am

it seems that it doesn't provide IP addresses to clients.
ip dhcp use vrf connected - no ip dhcp use vrf connected

I think that the "vrf" reference is an MPLS thing. I have seen
the positive form in 837's with no adverse effect on DHCP.

Maybe the default is (no entry in config that is)
"ip dhcp use vrf connected xyz"

Here is one that is working. (At least for DHCP:).

no ip dhcp use vrf connected
ip dhcp excluded-address 10.10.10.1
ip dhcp excluded-address 192.168.122.1 192.168.122.50
ip dhcp excluded-address 192.168.122.54
!
ip dhcp pool client
network 192.168.122.0 255.255.255.0
dns-server 192.168.5.12 192.168.7.12 213.120.62.103
domain-name qqq.com
netbios-node-type h-node
option 150 instance 1 ip 192.168.200.10
option 150 instance 2 ip 192.168.210.10
option 66 ascii "phone"
default-router 192.168.122.1
lease infinite

sh ip dhcp bin
Bindings from all pools not associated with VRF:
IP address Client-ID/ Lease expiration
Type
Hardware address/
User name
192.168.122.51 0100.1279.de12.bb Infinite
Automatic
192.168.122.53 0100.1279.dee3.b1 Infinite
Automatic
Guest
 

Re: DHCP not working on 837 - SOLVED

Postby AM » Fri Dec 16, 2005 12:20 pm

I have the same configuration but.............
Stupid me! I had an access lists on the interface ethernet0 that blocked all the DHCPREQUEST packets.
This the ACL

access-list 140 permit ip 10.135.3.96 0.0.0.31 192.168.31.0 0.0.0.255
access-list 140 permit ip 10.135.3.96 0.0.0.31 a.b.c.0 0.0.0.255
access-list 140 permit ip 10.135.3.96 0.0.0.31 e.f.g.0 0.0.0.255

put on the ethernet 0

but obviuously it blocks all DHCP packets. So the question is:

which is the source address and the destination address of a DHCP packet? Maybe 0.0.0.0 and 255.255.255.255?
How to specify better to leave passing through all DHCP requests? Maybe using an ACL with L2 addresses

Many thanks

Alex.
AM
 


Return to Cisco

Who is online

Users browsing this forum: No registered users and 0 guests

cron