Joined: 04 Oct 2007 Posts: 1261 Location: Ohio USA
Posted: Sun Nov 04, 2007 23:29 Post subject:
Yes. When you change the IP address of the router and apply the settings, the DHCP server will use an IP address range that the router is configured for. _________________ (05/02/17) std - 31924
Posted: Fri Jan 08, 2016 12:52 Post subject: Extending IP range
Hello people! My name is Ugljesa, and I'm new here on the forums!
So, my first question is very similar to this topic, so I didn't open a new one. Is it possible to extend the DHCP IP pool, and thus increase number of DHCP clients? Currently, I've set my router to assign IP addresses in the range from 10.0.0.1 to 10.0.0.253, and router is at 10.0.0.254. Can the local IP range be extended, so the DHCP can assign addresses from e.g. 10.0.0.0 to 10.255.255.255?
Hello, thanks for help! I've changed the subnet to one you suggested, but it seems to me that the router is still assigning only 253 addresses (from 10.0.0.1 to 10.0.0.253) even if I changed the subnet. And, in the DHCP settings it doesn't allow me to set max clients more than 253. Any ideas, or I am getting something wrong?
Not sure why the DHCP server (DNSMasq) would limit you to 253 hosts given that netmask, but perhaps it does have some internal limit of its own. Remember too, it has to store all that information in RAM, which is a limited resource in most routers. Or else it's just a bug.
I will add, using a netmask of 255.0.0.0 is ridiculous since it means a potential for 256^3 (16,777,216) hosts! Granted, nothing says you have to use all those hosts, but it could cause problems down the road.
For example, suppose you use a network search utility like nmap to enumerate all known devices on your local network. It will search, one by one, through 16 million IPs! Or consider what will happen if you decide to install an OpenVPN server. Since the OpenVPN client and OpenVPN server networks must be different and non-overlapping, every time you encounter a 10.x.x.x network on the road (and it will happen) and attempt to access your 10.0.0.0/255.0.0.0 network back home over the VPN, it won't work. You've created a home network that's so vast, it overlaps w/ every other subnet in the 10.x.x.x address space!
So if you need more than 254 usable hosts, just change the netmask slightly, say to 255.255.254.0 (/23), which will double your usable hosts to 510. That should be more than plenty for most ppl.
@eibgrad Yes, you're right, I'll listen your advice. Actually I don't need such a large pool at all, but I just wanted to try what the DHCP can do and play with it a bit.
AFAIK dd-wrt is still limited to 999 IP addresses.
Setting an IP/subnetmask with high range of hosts will usually work
but you will likely see conflicting info in GUI vs CLI dnsmasq.conf.
e.g. router IP 10.55.7.10/8 will have starting DHCP address as 10.0.0.1 regardless
of what starting IP you put in GUI (because 10.0.0.1 is the first address in that range)...
That range would be 10.0.0.1 - 10.255.255.254 (16,777,214 available hosts) .. it'll work using the first 999 IPs
but it's a bit confusing for dd-wrt software ...unless they have recently done some changes