On Monday 05 June 2023 at 00:08:13, o1bigtenor via Dng wrote:

> Should I switch my present router from 192.168.1.1 to my chosen
> 172.16.x.x (I'm running on dd-wrt)?

There is nothing inherently special about "192.168" or "172.16".

These used to fall into what were called "Class C" and "Class B" networks
respectively (and 10.0.0.0 was in Class A).

However these days everything is done based on netmasks (you'll come across
the abbreviation CIDR as well, meaning Classless Internet Domain Routing,
emphasising that the old Classes are no longer relevant).

Basic guide to netmasks:

1. 255.255.255.0 means that the first three numbers in the IP addresses on your
network are fixed (every machine has the same first three numbers in its
address) and the last number can be anything between 0 and 255.

2. 255.255.0.0 means the first two numbers are fixed, and the last two can each
be anything between 0 and 255.

3. I won't for the time being discuss netmasks which contain numbers other
than 0 or 255.

At this point it's useful to note that two addresses "disappear" from every
network range and cannot be assigned to machines on the network - the first
address and the last address. That means that a network of 255.255.255.0
which appears to leave you 256 addresses to play with, actually supports
"only" 254 machines.

Similarly, a netmask of 255.255.0.0, which leaves 256 x 256 = 65536 addresses
to play with, can have up to 65534 machines on the network.

Now, the interesting bit for you is that the entire range of addresses
192.168.0.0 up to 192.168.255.255 have been reserved (in document RFC 1918)
for "private use", and there is nothing to stop you deciding "right, I'll use
all of them, then" and setting your netmask to 255.255.0.0

That means you can have up to 65534 machines on your network using addresses
which all start with 192.168, just so long as every machine on the network has
a netmask of 255.255.0.0 (at present you'll be using 255.255.255.0).

So, to come back to the question you wanted to ask, which I've interpreted as
"should I change my router's IP address from 192.168.1.1 to something in the
172.16.x.x range so that I have more IP addresses to play with?", my answer is
"no - just change your netmask to 255.255.0.0 and carry on using 192.168.1.1
for your router's address".

The only two addresses in the range which you cannot use are 192.168.0.0 and
192.168.255.255.

I think the rest should be sufficient for your needs - however I do wonder what
size switches you have to join this lot together with :)


Antony.

--
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https://en.wikipedia.org/wiki/Pretty_Good_Privacy

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