[c-nsp] DHCP problems trunked C2924 to C1841

[Aaron Riemer]

Hi there, 

You mention you have a problem with DHCP. Does this mean that you have
connectivity when assigning static IP's to workstations on each respective
vlan? 

If not I would check two things.  

1. The native vlan of the switch is vlan 1 (should be by default)
2. Check that all vlan's are allowed over the trunk.

Cheers,

Aaron.

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Moerman, Maarten
Sent: Thursday, 23 August 2007 7:54 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] DHCP problems trunked C2924 to C1841

Hello,

I've got a little problem on my home network regarding DHCP.

I have a C1841, and a C2924XL, which have a trunk between them.

I've setup 3 vlans, everything is working fine , however I can't get to
get DHCP working on the C1841. I'd like to have the first vlan dhcp
being served by a linux server (will be moved to the cisco in the
future), and the 2nd and third vlan dhcp being served by the C1841.


This is my config:

FastEthernet0/22 of the C2924XL is connected to FastEthernet0/0 of the
C1841.


ip dhcp excluded-address 172.24.0.2
ip dhcp excluded-address 172.24.0.3
!
ip dhcp pool buren
   network 172.24.0.0 255.255.255.0
   default-router 172.24.0.1
   dns-server 212.142.28.66
!
ip dhcp pool maarten
   network 172.25.0.0 255.255.255.0
   default-router 172.25.0.1
   dns-server 212.142.28.66
!
interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip address 172.23.0.1 255.255.255.0
 ip nat inside
 ip virtual-reassembly
 no ip route-cache
!
interface FastEthernet0/0.2
 encapsulation dot1Q 2
 ip address 172.24.0.1 255.255.255.0
 ip access-group 124 in
 ip nat inside
 ip virtual-reassembly
 no ip route-cache
!
interface FastEthernet0/0.3
encapsulation dot1Q 3
 ip address 172.25.0.1 255.255.255.0
 ip access-group 125 in
 ip helper-address 172.23.0.1
 ip nat inside
 ip virtual-reassembly
 no ip route-cache
!
access-list 124 deny   ip 172.24.0.0 0.0.0.255 172.23.0.0 0.0.0.255
access-list 124 deny   ip 172.24.0.0 0.0.0.255 172.25.0.0 0.0.0.255
access-list 124 permit ip 172.24.0.0 0.0.0.255 any
access-list 125 deny   ip 172.25.0.0 0.0.0.255 172.23.0.0 0.0.0.255
access-list 125 deny   ip 172.25.0.0 0.0.0.255 172.24.0.0 0.0.0.255
access-list 125 permit ip 172.25.0.0 0.0.0.255 any


And of course a lot of other things which aren't interesting for this
audience. ACL's arent' the problem I think, because with debugging I
don't see them hitting the ACL's.

This is my C2924Xl config:

interface VLAN1
 ip address 172.23.0.3 255.255.255.0
 no ip directed-broadcast
 no ip route-cache
!
interface VLAN2
 description vlan 2
 ip helper-address 172.23.0.1
 no ip directed-broadcast
 no ip route-cache
 shutdown
!
interface VLAN3
 description vlan 3
 ip helper-address 172.25.0.1
 no ip directed-broadcast
 no ip route-cache
 shutdown
!
interface FastEthernet0/21
 switchport access vlan 2
 spanning-tree portfast
!
interface FastEthernet0/22
 switchport trunk encapsulation dot1q
 switchport mode trunk
end

If I set all the debugging info there is, I cannot see any request for
vlan2 + 3 passing by.

Anyone have a clue?

--
Network Engineer | eBay / Marktplaats.nl Randweg 25 | 8304 AS Emmeloord 
E-mail: mmoerman at ebay.com | Mobile: +31 6 55 1 222 47


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