Re: [lwip-users] DHCP end of lease time

[Sergio R. Caprile]

AFAIK, you will renew your lease, not get a new address.
Your address can't be taken as you are using it.
The server will assign a new address if you'be been out and your lease 
expired and the address was reused and assigned to someone else while 
you were out.

Let's assume you do have a new address.
All other machines will need to know that, since you said you have 
servers. How did they find you in the first place ? (*)
You can configure a DNS to talk to the DHCP server and resolve that, but 
you can also configure the DHCP server to assign a fixed address to your 
machine, and so always the same address.
If you don't:
	name resolution results in local caches will cause those machines to 
fail on trying to reach you until those caches expire.
        you must have a DNS server because you don't have an invariable address.
		(*) However, you can write a discovery protocol and provide your 
clients a tool to find you...

Besides that, UDP will probably happily survive; however, if you fill 
your bindings with the other end address, you'll need to unbind and 
rebind as when your application session is done.
Open TCP connections will surely fail, so you will need to shut them off.

I don't think there is something that requires you to restart your 
servers, as long as you are not storing your former IP somewhere; the 
problem, if I'm not missing something, is with open connections.

Do yourself a favor and just request the admin to add this:
               host MyHostName {
                        hardware ethernet <my MAC>;
                        fixed-address <my IP>;
               }
Where <my IP> must be out of the dynamic pool
(well, assuming they run Linux and dhcpd...)