The Structure of and IP Address / 32 bit address

[DreamSeller]

Learnt this at my todays IT courses and i thought it would be great to share with you guys

 

[FordGT90Concept]

That's just binary -> decimal conversion. It's the packet structure that is interesting.

 

[Deleted member 3]

Next he's gonna learn to calculate netmasks

 

[hat]

What? 1=1? WHY WAS I NOT INFORMED OF THIS

 

[Mussels]

i learned all that stuff and then forgot it... the theory was 100% useless when setting up networks, in practical use.

 

[FordGT90Concept]

i learned all that stuff and then forgot it... the theory was 100% useless when setting up networks, in practical use.

Yup, just remember 192.168.0.1 or whatever. It isn't hard to convert that to hex:
C0A80001

Or binary:
11000000101010000000000000000001

 

[hat]

What is 192.168.0.1 used for?

 

[Mussels]

What is 192.168.0.1 used for?

usually a router/DHCP server

 

[FordGT90Concept]

Yup, that's the default router IP for D-Link routers.

The following are reserved for intranet use:
10.#.#.#
172.16.#.#
192.168.#.#

172.0.0.1 is reserved for loopback (aka localhost).

 

[Deleted member 3]

Yup, that's the default router IP for D-Link routers.

The following are reserved for intranet use:
10.#.#.#
172.16.#.#
192.168.#.#

172.0.0.1 is reserved for loopback (aka localhost).

And many other brands. Most routers have either 192.168.x.1, 192.168.x.100 or 192.168.x.254. Something in the 10.x.x.x is more rare, never seen the 172.16.x.x range used as default setting, not sure why.

 

[Mussels]

And many other brands. Most routers have either 192.168.x.1, 192.168.x.100 or 192.168.x.254. Something in the 10.x.x.x is more rare, never seen the 172.16.x.x range used as default setting, not sure why.

the 10.0.0.x range is very common here in australia, Telstra modems and routers all use it. (usually on really shit hardware too)

 

[hat]

I've had only 2 routers and they were both 192.168.1.1

While we're talking about networking... what happens if you want more than 155 computers on a network (slots 192.168.x.100 - 192.168.x.255 are used up)

 

[Mussels]

I've had only 2 routers and they were both 192.168.1.1

While we're talking about networking... what happens if you want more than 155 computers on a network?

you get 255, minus the router.

If you want more, you need to segregate into class C subnets, 192.168.0.1 for 254 users, 192.168.1.1 for the others. Set the subnet mask to 255.255.0.0 and communication will be possible between them, they merely need the gateway IP address set to the router and everything will be well.

where did starting at 100 come from? it starts at 1

 

[FordGT90Concept]

And many other brands. Most routers have either 192.168.x.1, 192.168.x.100 or 192.168.x.254. Something in the 10.x.x.x is more rare, never seen the 172.16.x.x range used as default setting, not sure why.

192.168.#.# is definitely the most common. A Netgear I worked with for some reason thought 192.168.#.# was in use so it fell back to 10.#.#.# (99% sure it was faulty though). I, too, have never seen 172.16.#.# but, it is reserved for intranet use by IANA.

Apparently, 192.168.#.# has 65k addresses, 172.16.#.# has a 1,000k addresses, and 10.#.#.# has 16,000k addresses. I assume that, if 192.168.#.# isn't enough (consumer-class), they go straight to 10.#.#.# (enterprise-class) skipping the 172.16.#.# range.

http://en.wikipedia.org/wiki/Private_network

 

[DreamSeller]

i learned all that stuff and then forgot it... the theory was 100% useless when setting up networks, in practical use.

very very true
im so noob at this fckn theory i wish we had the test in practice form

 

[FordGT90Concept]

where did starting at 100 come from? it starts at 1

D-Link...
Device = 192.168.0.1
DHCP = 192.168.0.100-192.168.0.199

Netopia (aka Motorola)...
Device = 192.168.1.254
DHCP = don't use it

But yeah, the router is almost always at 192.168.0.1 or 192.168.1.1

 

[AltecV1]

wow that is complicated