DHCP query

[glennda]

I have just moved our dhcp server from an old one to the new. On our old server there was exclude from distribution for address ending 254-1 on the end of each "range" for example between 192.168.1.254-192.168.2.1.

I had heard lots of stories about the guy who setup the system and just thought it was a bit strange and it was one of those things so i didn't copy the whole lot over just set it up how i would normally with just excluded my range for my servers and other static machines so 192.168.1.1 - 192.168.1.100 and setup the scope with a full range from 192.168.1.1 through to 192.168.15.254. but then i noticed the other day that a machine had the ip address 192.168.5.0 which is had been leased by the dhcp server.

 

I'm thinking that this is wrong and that nothing should be using this address.

 

Am I just an idiot or should a dhcp server not to give out these addresses? ( i have now reset up the exclusions as im not sure!)

 

the only support article i can find is for nt4!

[User3204]

I think it's just bad practice.. I don't think there's anything wrong with using these IPs, it's perhaps just because some (crappy) software will assume a w.x.y.255 is a broadcast and ignore it.

 

We have 24 bit ranges split up per VLAN, so we have w.x.y.1 and .2 as routers, and there's a good reason for not using w.x.y.0

[itwasntme]

assuming it's a flat network, i.e. no vlans and your netmask is 255.255.240.0 (er... 255.255.241.0?) then you're fine. 192.168.1.0 is your network identifier where as 192.168.15.255 would be your broadcast address

[powdarrmonkey]

What's your subnet mask and IP range?

[glennda]

our ip range goes from 192.168.112.1 through to 192.168.124.254 with exeptions for 192.168.112-113 and 119/122. (112-113 are statics for servers/printers, 119 used to be the end of our scope so was also left for statics, but scope was extended, 122 causes problems as it was the virtual bridge address that KVM uses and any machine with a 122 address can not talk to any vm's - so half the domain!)

 

subnet mask is 255.255.240.0 ( i know its wrong but is there incase of futher expansion, saves changing all machines on statics again!)

[powdarrmonkey]

In that case no, there is no reason not to use those addresses (apart from badly written software, as User2304 pointed out).

[glennda]

In that case no, there is no reason not to use those addresses (apart from badly written software, as User2304 pointed out).

 

cool i just wasn't 100% sure as all the people in the office none of use could decide for definite. I will keep the exclusions in there just incase there is some stupid software which kicks up a fuss at the end of the day its only about 12 addresses so no major problem don't want any other random problems - the 122 range was a rather strange problem until we worked that one out!

[powdarrmonkey]

Always consult a subnet calculator (unless you enjoy doing it in your head) if in doubt.

[glennda]

Always consult a subnet calculator (unless you enjoy doing it in your head) if in doubt.

 

or ask the good old people of edugeek!

 

thanks for the advice - this is the support article that got me more confused Client's Valid <x>.<x>.<x>.0 Host Address Is Disallowed on the Network but as it says only applies to nt4 and workstation 4.0 at which time i was just about to start or at primary school!