erorr overlaps with FastEthernet0/0

[baher 1]

i have ip add 10.0.1.0 and i make vlsm
to have 2 network each 30 and 60 hosts

10.0.1.0 /27 ---- 30 shost
10.0.1.32/26 ---- 60 shost

and i make this config.



R0#config t
Enter configuration commands, one per line. End with CNTL/Z.
R0(config)#int f0/0
R0(config-if)#ip add 10.0.1.1 255.255.255.224
R0(config-if)#int f1/0
R0(config-if)#ip add 10.0.1.33 255.255.255.192
% 10.0.1.0 overlaps with FastEthernet0/0

what's wrong

[crissa]

i have ip add 10.0.1.0 and i make vlsm
to have 2 network each 30 and 60 hosts

10.0.1.0 /27 ---- 30 shost
10.0.1.32/26 ---- 60 shost

and i make this config.



R0#config t
Enter configuration commands, one per line. End with CNTL/Z.
R0(config)#int f0/0
R0(config-if)#ip add 10.0.1.1 255.255.255.224
R0(config-if)#int f1/0
R0(config-if)#ip add 10.0.1.33 255.255.255.192
% 10.0.1.0 overlaps with FastEthernet0/0

what's wrong

Hello,
a /27 with the subnet nask 255.255.255.224 has 32 IP addresses, it starts at 0, 32, 64, 96, 128, 160, 192 and 224.
A /26 with the subnet mask 255.255.255.192 has 64 IP addresses, it starts at 0, 64, 128 and 192.

You try to configure two subnets that both start a 0. The first 32 IP addresses of the /26 overlaps with the /27.

HTH!
Bye, Tore

[baher 1]

Hello,
a /27 with the subnet nask 255.255.255.224 has 32 IP addresses, it starts at 0, 32, 64, 96, 128, 160, 192 and 224.
A /26 with the subnet mask 255.255.255.192 has 64 IP addresses, it starts at 0, 64, 128 and 192.

You try to configure two subnets that both start a 0. The first 32 IP addresses of the /26 overlaps with the /27.

HTH!
Bye, Tore

how i resolve this problem
i wnant use ip 10.0.1.0 to make 2 network have 30 & 60 hosts

[crissa]

how i resolve this problem
i wnant use ip 10.0.1.0 to make 2 network have 30 & 60 hosts

Hello,
you could use:

10.0.1.0/27
10.0.1.64/26

But that creates 32 unused IP addresses (10.0.1.32/27). So please use:

10.0.1.64/27
10.0.1.0/26

HTH!
Bye, Tore

[baher 1]

Hello,
you could use:

10.0.1.0/27
10.0.1.64/26

But that creates 32 unused IP addresses (10.0.1.32/27). So please use:

10.0.1.64/27
10.0.1.0/26

HTH!
Bye, Tore

thx u i tray it and it's ok
i use use /26 then /27 in this example
can i make it rule i use less mask then larger number of mask

for other example want make 3 network have 120 & 10 & 9 hosts
in ip add 10.0.1.0

10 hosts = /28 120 host = /25 5 hosts = /29

so be use /25 then /28 then /29

10.0.1.0/25
10.0.1.128/28
10.0.1.144/29

is my Deductive true or not ??? and if not why ????

[crissa]

[...]
for other example want make 3 network have 120 & 10 & 9 hosts
in ip add 10.0.1.0

10 hosts = /28 120 host = /25 5 hosts = /29

so be use /25 then /28 then /29

10.0.1.0/25
10.0.1.128/28
10.0.1.144/29

is my Deductive true or not ??? and if not why ????

Hello,
you don't have to sort the subnets from greater subnets down to smaller subnets. You could also use:

10.0.1.0/25
10.0.1.128/29
10.0.1.144/28

Maybe it helps you to write down start and end of a subnet:

10.0.1.0/25 => 0 ... 127
10.0.1.128/28 => 128 ... 143
10.0.1.144/29 => 144 ... 151

or

10.0.1.0/25 => 0 ... 127
10.0.1.128/29 => 128 ... 135
10.0.1.144/28 => 144 ... 159

The /28 can't start at 136 as you can't divide 136 by 16. By you can divide 144 by 16!

HTH!
Bye, Tore

[baher 1]

ok

sorry last question

i have ip add 10.0.0.0
and i wnat make 3 network
have 600 & 500 & 100 hosts
what is the Solution

[crissa]

ok

sorry last question

i have ip add 10.0.0.0
and i wnat make 3 network
have 600 & 500 & 100 hosts
what is the Solution

Hello,
one solution is:

600 => 1024 => /22
500 => 512 => /23
100 => 128 => /25

10.0.0.0/22
10.0.4.0/23
10.0.6.0/25

HTH!
Bye, Tore