DHCP client nonstandard behavior

[Christof Chen]

Sending a Renewal originating from a real IP is perfectly valid (and the
intended behavior).

Christof Chen


Christian Treczoks schrieb:
> Dear Listmembers,
> 
> I am new to this mailing list, and the question might have been asked 
> before, although I could not find anything in the archives regarding my 
> problem.
> 
> I'm using an RTOS (Keil RL-ARM) with a simple TCP/IP stack (Library, no 
> source) for my project. Now I need to implement DHCP client functionality 
> into my project, but not as the designer of the stack intended it to be 
> (they only support DHCP when you start the system, you can disable it 
> during runtime, but not re-enable it).
> 
> So I read the docs and DHCP sufficiently easy to implement, if it wasn't 
> for one point: The RFCs state that the clients sender address is to be 
> 0.0.0.0 and the recipient address should be 255.255.255.255. This is ok 
> for the initial DISCOVER and REQUEST packets, but when I need to renew the 
> lease, I can't create a UDP packet with 0.0.0.0 as the sender address - 
> the library uses the systems' IP address as the sender address.
> 
> If I would send a REQUEST package (for a renewal) with a valid, previously 
> negotiated sender address that is not 0.0.0.0 (but everything else ok), 
> would this cause problems with existing DHCP servers?
> 
> Yours,
> Christian Treczoks
> 
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