Command line tool for emulating DHCP-client

Ragnar Lonn ragnar at
Fri Aug 24 16:36:21 UTC 2007

We also have a tool, DHCPTOOL, that can be used to emulate mostly any 
kind of broken DHCP client behaviour.

It can be downloaded from



Tim Peiffer skrev:
> There are multiple methods to do what you request. The one I have used 
> is dhcping.
> That said, why? I know you said you wanted to send a DHCPRELEASE on 
> behalf of the clients. That is fine for cleaning up a lease database, 
> but the release information is never sent back to the client, and the 
> client does not know that its lease is no longer valid. If the client 
> presents with the same address through a DHCPREQUEST, the DHCP server is 
> supposed to honor it, presuming the lease isn't already in use, and that 
> the address is consistent with the network that sourced the DHCPREQUEST. 
> In my opinion, unless the client is given a new lease on another network 
> or from another part of the pool, sending a DHCPRELEASE breaks the 
> protocol assumptions.
> Regards,
> Tim Peiffer
> Network Support Engineer
> Networking and Telecommunications Services
> University of Minnesota/Northern Lights GigaPOP
> dhcping - send a DHCP request to DHCP server to see if it’s up and
> running
> [..]
> The client either sends a DHCPREQUEST or DHCPINFORM packet to the
> server and waits for an answer. Then, if a DHCPREQUEST was send, it
> will send a DHCPRELEASE back to the server.

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