subnet 255.255.252.0 and 255.255.255.0

ayjayoh21 · 02-04-2007, 20:07

Connected modem --- pc i have a subnet mask of 255.255.252.0
connected modem --- router --- pc i have a subnet mask of 255.255.255.0

could this be my problem outlined here -

http://www.cableforum.co.uk/board/87...gin-media.html

I don't really know what subnets do. . . . .

DocDutch · 02-04-2007, 20:11

modem to pc is normal to have a subnet like that. as the IP, gateway and DNS are totally different from eachother.

router to pc its normal to have a 255.255.255.0 subnet as all the ips are in the same net (lan ip, gateway and DNS address)

02-04-2007, 20:13

You'll also find that connected modem ... PC gives you an IP address of something like 81.x.x.x or 2xx.x.xx (This is your public IP address, so don't post in full here). Connected modem ... router ... pc will give you a private IP address, something like 192.168.x.x.

Connected modem ... pc gives the PC an IP address and sub-net issued by Virgin. Connected modem ... router ... PC gives the ROUTER an external IP addrss and sub-net issued by Virgin. The router then gives each connected PC a private IP address and sub-net.

Hope this helps.

[Edit] DD beat me to it.

rikur · 03-04-2007, 21:29

Quote:

Originally Posted by ayjayoh21

I don't really know what subnets do. . . . .

Subnets simply denote which devices are on your local network and which devices need to be reached via your router/cable modem.

http://www.fairlyuseful.co.uk/subnets/details.php has laborious detail

ayjayoh21 · 04-04-2007, 07:21

Cheers Gents,

Quote:

Originally Posted by JohnHorb

You'll also find that connected modem ... PC gives you an IP address of something like 81.x.x.x or 2xx.x.xx (This is your public IP address, so don't post in full here). Connected modem ... router ... pc will give you a private IP address, something like 192.168.x.x.

Yep - that is correct.

I now understand that subnets are not static.

So my worry that my router had a subnet of 255.255.255.0 and my modem had a subnet of 255.255.252.0 and this was why I could not connect to the internet using the router was way off the mark. I just presumed they would not be able to communicate on different subnets.

Back to the drawing board, as it still isn't working.

Xaccers · 04-04-2007, 16:37

I found thinking of subnets as fences around groups of IP addresses the easiest way to get my head around them.