Subnetting question

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Guest

Subnetting question

Post by Guest » Wed Jul 30, 2008 9:46 pm

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

Guest

Re:Subnetting question

Post by Guest » Wed Jul 30, 2008 11:07 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

Post by Guest » Wed Jul 30, 2008 11:34 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

Post by Guest » Thu Jul 31, 2008 12:04 am

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

Post by Guest » Thu Jul 31, 2008 1:29 am

shf-gw1(config)#interface vlan1shf-gw1(config-if)# ip address 203.148.0.255 255.255.255.0 secondaryBad mask /24 for address 203.148.0.255shf-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 secondaryshf-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 msshf-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 vlan1Building 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 30end 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 msReply to request 1 from 192.168.160.1, 1 msReply to request 1 from 192.168.5.254, 1 msReply to request 1 from 192.168.5.102, 1 msReply to request 1 from 192.168.5.103, 1 msReply to request 1 from 192.168.5.3, 1 msReply to request 1 from 192.168.5.1, 1 msReply to request 2 from 192.168.160.1, 1 msReply to request 2 from 192.168.5.254, 1 msReply to request 2 from 192.168.5.102, 1 msReply to request 2 from 192.168.5.103, 1 msReply to request 2 from 192.168.5.3, 1 msReply to request 2 from 192.168.5.1, 1 msReply to request 3 from 192.168.5.1, 1 msReply to request 3 from 192.168.160.1, 1 msReply to request 3 from 192.168.5.254, 1 msReply to request 3 from 192.168.5.102, 1 msReply to request 3 from 192.168.5.103, 1 msReply to request 3 from 192.168.5.3, 1 msReply to request 4 from 192.168.160.1, 1 msReply to request 4 from 192.168.5.254, 1 msReply to request 4 from 192.168.5.103, 1 msReply to request 4 from 192.168.5.102, 1 ms   thanks NT , like this , i understood .. very clear

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