Maximum Scope of Class B network

[ericargyle]

Question, currently our network has a DHCP scope of 172.17.6.2 to 172.17.9.250. I would like to expand it to 172.17.6.2 to 172.17.30.250. Is this possible? Just double-checking before expansion.

[allen2]

No if you need this much new addresses including your existing ones, you'll have to use 172.17.0.0 /19 network which will allow you to use ip between 172.17.0.0 and 172.17.31.255 and replace the subnet mask 255.255.224.0. The only way to do it properly, if you're using the 172.17.0.0 ->172.17.5.255 for another physical network, would be to make vlans but as your actual subnet isn't a classic one you might get errors. Check a good subnet calculator there: http://jodies.de/ipcalc?host=172.17.6.0&mask1=22&mask2=.

[ericargyle]

Cheers Allen. One more question, because I don't want to change the subnet in the middle of the year, what about keeping it at 172.17.6.2 to 172.17.15.250? Will that work?

[allen2]

Yes it will if you change the subnet mask to 255.255.240.0 but you'll also see the network 172.17.0.0-172.17.5.255 so it might create problems if, for example, it is routed to another site.