Connection drop on DHCP release

[seanx]

Im setting up a DHCP server for a LAN Party but Im haveing a bit of a problem. We want to have a semi short lease time on the server so if we need to change something(ie. change DNS server) they will get the new settings relatively quick.
Well for some reason I always thought when you had a lease and the lease was up it would just try to renew it befor it dropped your connection and re-leased your information. And well during a LAN party thats bad. You cant have peoples connections dropping every 5 minutes.

Im running dhcpd3 on a linux box and was just wondering if there was anyway to work around this. Ive been reading everything I can find on google about it and havent found anything.

Ill get back to looking around.

Any help is appreaciated,

--Sean

 

[Party2go9820]

Im setting up a DHCP server for a LAN Party but Im haveing a bit of a problem. We want to have a semi short lease time on the server so if we need to change something(ie. change DNS server) they will get the new settings relatively quick.
Well for some reason I always thought when you had a lease and the lease was up it would just try to renew it befor it dropped your connection and re-leased your information. And well during a LAN party thats bad. You cant have peoples connections dropping every 5 minutes.

It doesn't "drop" your connection when renewing - only if the it is unable to talk to the server and has to negotiate a new lease is there any possibility of dropping the connection. The clients will try to renew 1/2 through the lease to avoid the whole "DORA" process if it can. If your DHCP server is ok, and your clients can talk to it problem free, then you won't have any problems at your LAN party.

 

[seanx]

Hmm, I still believe there must be something wrong with my dhcp server then.

I was doing some testing and in windows XP if I go and "repair" my connection when I already have an IP address it fails saying it cant renew my IP address and in the event viewer I have this error...

Your computer was not able to renew its address from the network (from the DHCP Server) for the Network Card with network address 000C7636AA68. The following error occurred:
The semaphore timeout period has expired. . Your computer will continue to try and obtain an address on its own from the network address (DHCP) server.

And looking at my event viewer it looks like there are about 1000 entriers for that error, for when it tries to refresh the IP befor the lease is up.

But when testing and I do not currently already have a leased IP, it hands me out one no problem, I get everything is a split second.

Something weird is going on


--Sean

 

[seanx]

Oh I want to hit myself. I checked out my logs in /var/log/syslog and I just happaned to notice this

May 10 09:32:34 pancake dhcpd: DHCPREQUEST for 10.0.3.1 from 00:0c:76:36:aa:68 via eth1
May 10 09:32:34 pancake dhcpd: DHCPACK on 10.0.3.1 to 00:0c:76:36:aa:68 via eth1
May 10 09:32:34 pancake dhcpd: send_packet: Operation not permitted
May 10 09:32:34 pancake kernel: Shorewall:all2all:REJECT:IN= OUT=eth1 SRC=10.0.0.1 DST=10.0.3.1 LEN=328 TOS=0x00 PREC=0x00 TTL=64 ID=107 DF PROTO=UDP SPT=67 DPT=68 LEN=308

Yeah so my firewall has a new rule and everything works like a charm

--Sean