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New Member

DMVPN and DHCP

I have a laptop connected to an 871 router that connects to the network successfully using DMVPN. I have a DHCP scope setup on the remote router. The laptop is supposed to pull an IP address from the DMVPN termination point, it doesn't. I enabled debug IP dhcp server packet so I can at least see if the traffic is making it to the distant router which it is, so the traffic is passing the traffic through the tunnel. Does anyone have any thoughts on this?

3 REPLIES
New Member

Re: DMVPN and DHCP

Hi,

I forgot to write this one please check what is the IP address offer given by the remote router is it in the same subnet which is required by the client since there could be more than once scope on Remote router .

Remember to rate useful posts.

Deepak

New Member

Re: DMVPN and DHCP

Hi,

As i understand Laptop is sending the DHCP Discover message, which will have destinated address as broadcast 255.255.255.255 .Please check whether the debug result shows any DHCP Offer from the remote router.If there is a DHCP offer check out the DHCP Ack from cleint mac address ( check mac address on Application layer not data link layer) to Remote Router (DHCP server) .

The reason for ip address not allocated to Laptop could be.

1.Client might be asking for the particulat IP address and IP address is not available so the client might be sending DHCP decline message.

2.The case could be Laptop could be asking for any DHCP option among (0-255 ) which might not be available with the remote router acting as dhcp server,the reason could be next-server address not configured/reachable on Remote router.Normally client accept the ip address even if options are not there but sometime it does not.

Please check using packet sniffer on Laptop (eg. Ethreal ) that is there any DHCP NAK send by remote router .

Remember to rate useful posts.

Deepak

New Member

Re: DMVPN and DHCP

Hi,

As i understand Laptop is sending the DHCP Discover message, which will have destinated address as broadcast 255.255.255.255 .Please check whether the debug result shows any DHCP Offer from the remote router.If there is a DHCP offer check out the DHCP Ack from cleint mac address ( check mac address on Application layer not data link layer) to Remote Router (DHCP server) .

The reason for ip address not allocated to Laptop could be.

1.Client might be asking for the particulat IP address and IP address is not available so the client might be sending DHCP decline message.

2.The case could be Laptop could be asking for any DHCP option among (0-255 ) which might not be available with the remote router acting as dhcp server,the reason could be next-server address not configured/reachable on Remote router.Normally client accept the ip address even if options are not there but sometime it does not.

Please check using packet sniffer on Laptop (eg. Ethreal ) that is there any DHCP NAK send by remote router .

Remember to rate useful posts.

Deepak

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