DOH!! Ok, when setting serial 0/0 on PIR2 to 195.10.1.2/30 it says it overlaps with fastethernet 0/0 195.10.1.0. Cheers.

coolboarderguy

Hi All,

obviously I'm doing something fundamentally wrong here? Cheers.

Gateway of last resort is not set

195.10.1.0/25 is subnetted, 1 subnets

C 195.10.1.0 is directly connected, FastEthernet0/0

coolboarerguy

Yes something is fundamentally wrong here. A basic concept of IP addressing and subnetting is that the same subnet should not exist in more than 1 place in the network. But you have taken the same /24 (class C) network and created serial link (/30) subnets and LAN (/25) subnets.

"PIR2 also has an IP 195.10.1.5/25 on the fastethernet 0/0 and PIR3 has an IP 195.10.1.6/25"

This puts the same /25 subnet on 2 different routers and the LAN subnet is using the same address space as the serial links.

My suggestion is to start over and plan a more effective addressing scheme.

HTH

Rick

Hi All,

ok, what's being said here, is, you can define larger subnet ranges and then break it down into smaller ones, IP/25 and then IP/30, but not IP/30 and then IP/25, yes? Cheers.

coolboardeguy

Yes your absolutely right. Always go from high to low i.e. high no of users to low.This the best practice.

HTH.

Cheers,

Nikhil

Nikhil

There is a serious problem in your suggestion. You suggest this:

PIR2-195.10.1.1/25

PIR3-195.10.1.2/25

but this means that the same subnet will exist in 2 different places. Both of those addresses describe a subnet which starts at 195.10.1.1 and goes through 195.10.1.127. It is a problem if you try to put the same subnet on 2 different routers. If you want at least 2 LAN subnets and some serial subnets to all come out of a /24 (class C) address space then the LAN subnets can not be larger than /26 (instead of /25). With /25 there are only 2 subnets in the address space. With /26 you can have 4 subnets.

HTH

Rick

Rick,

I think u hv taken me in wrong way.I'll elaborate it for you.

PIR1-195.10.1.0/25-PIR2-195.10.1.128/30-PIR3

Cheers,

Nikhil E.