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Subnetting question

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Subnetting question

Postby Guest » Wed Jul 30, 2008 8:46 pm

Hi all,

 

Can someone explain why these 2 ip addresses are correct and show how the ips where achieved. Thanks

Guest
 

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Re:Subnetting question

Postby Guest » Wed Jul 30, 2008 10:07 pm

Hello,

 

The first one is invalid because all the host bits are zeros (last 9 bits are host bits for a 255.255.254.0 mask)

 

The second one is a valid address as the host bits will be 100000000 (This satisfies the condition that all host bits should not be zeros)

 

Third one is invalid because all host bits are ones

 

Fourth one is valid because the host bits are 011111111

 

Last one is invalid because again all the host bits are zeros.

 

Hope this helps.

 

Regards,

 

NT

Guest
 

Re:Subnetting question

Postby Guest » Wed Jul 30, 2008 10:34 pm

hello ,

 

i have one question,, i donnot understand whether this ip add can assign to a host . please help

 

 

203.148.0.255 / 255.255.254.0

 

i know netmask 255.255.254.0   broadcast address is  203.148.1.255 . 

Guest
 

Re:Subnetting question

Postby Guest » Wed Jul 30, 2008 11:04 pm

Hello,

 

If you have enabled "IP classless" feature, then you can assign that address. If not, that is an invalid address as 203.x.x.x is a Class C address and the default (classful) mask is 255.255.255.0

 

Hope this helps.

 

Regads,

 

NT

Guest
 

Re:Subnetting question

Postby Guest » Thu Jul 31, 2008 12:29 am

shf-gw1(config)#interface vlan1

shf-gw1(config-if)# ip address 203.148.0.255 255.255.255.0 secondary

Bad mask /24 for address 203.148.0.255

shf-gw1(config-if)# ip address 203.148.1.0 255.255.254.0 secondary 

shf-gw1(config-if)# ip address 203.148.0.255 255.255.254.0 secondary

shf-gw1(config-if)#     

shf-gw1(config-if)#

shf-gw1(config-if)#do ping 203.148.1.0 re 100

 

Type escape sequence to abort.

Sending 100, 100-byte ICMP Echos to 203.148.1.0, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (100/100), round-trip min/avg/max = 1/1/9 ms

shf-gw1(config-if)#do ping 203.148.0.255 re 100

 

Type escape sequence to abort.

Sending 100, 100-byte ICMP Echos to 203.148.0.255, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (100/100), round-trip min/avg/max = 1/1/9 ms

 

shf-gw1(config-if)#do show run interface vlan1

Building configuration...

 

Current configuration : 178 bytes

!

interface Vlan1

ip address 203.148.1.0 255.255.254.0 secondary

ip address 203.148.0.255 255.255.254.0 secondary

ip address 192.168.5.45 255.255.255.0

load-interval 30

end

 

shf-gw1(config-if)#

 

shf-gw1(config)# do ping 192.168.5.255

 

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.5.255, timeout is 2 seconds:

 

Reply to request 0 from 192.168.5.1, 16 ms

Reply to request 1 from 192.168.160.1, 1 ms

Reply to request 1 from 192.168.5.254, 1 ms

Reply to request 1 from 192.168.5.102, 1 ms

Reply to request 1 from 192.168.5.103, 1 ms

Reply to request 1 from 192.168.5.3, 1 ms

Reply to request 1 from 192.168.5.1, 1 ms

Reply to request 2 from 192.168.160.1, 1 ms

Reply to request 2 from 192.168.5.254, 1 ms

Reply to request 2 from 192.168.5.102, 1 ms

Reply to request 2 from 192.168.5.103, 1 ms

Reply to request 2 from 192.168.5.3, 1 ms

Reply to request 2 from 192.168.5.1, 1 ms

Reply to request 3 from 192.168.5.1, 1 ms

Reply to request 3 from 192.168.160.1, 1 ms

Reply to request 3 from 192.168.5.254, 1 ms

Reply to request 3 from 192.168.5.102, 1 ms

Reply to request 3 from 192.168.5.103, 1 ms

Reply to request 3 from 192.168.5.3, 1 ms

Reply to request 4 from 192.168.160.1, 1 ms

Reply to request 4 from 192.168.5.254, 1 ms

Reply to request 4 from 192.168.5.103, 1 ms

Reply to request 4 from 192.168.5.102, 1 ms

 

 

 

thanks NT , like this , i understood .. very clear

Guest
 



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