[j-nsp] DHCP static bindings on J2320

[Alexander Shikoff]

On Thu, Jul 16, 2009 at 11:15:48AM -0700, David Sinn wrote:
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> I've noticed the same problem on my J's too.  Looks to be a uniqueness  
> in the implementation of the DHCP server in JunOS.  DHCPd under Linux  
> and Cisco's built-in DHCP server do not exhibit the same behavior.
> 
> What I've been able to track it to is that it is a interaction when  
> the client re-requesting the address it originally had since it does  
> not believe that it has expired.  So when the client comes back up it  
> promptly does a DHCP-request to re-validate the address is still OK to  
> use.  The server happily give the address back to them (it's not in  
> use since you cleared it), and ignores the static.  That   would imply  
> that statics only come into play when a DHCP-Discover is generated by  
> a client and not validated when a DHCP-request comes in.
> 
> The way I got around it was to clear the lease, plop the device onto a  
> wholly different network allowing it get a different address there and  
> then move it back.  Since the client no longer has a address that will  
> work correctly with just a DHCP-request, it has to do a DHCP-discover  
> and gets the new static in the DHCP-offer response.

Hello,

it seems for me that J2320's DHCP server still offers IP address from dynamic 
pool because of active ARP entry for dynamic IP address.

I've cleared dynamic binding, cleared ARP entry, and after that DHCP
offered address from static binding.

-- 
MINO-RIPE