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question about ip commands -


there four commands about ip that i don't quiet understand -

if someone could explain me even a little i would be very grateful

what the command - no ip directed-broadcast mean ?

what the command - ip classless mean ?

what the command ip subnet-zero mean ?

and last the command no fair-queue

that it-


Community Member

Re: question about ip commands -

ip commands:

no ip directed-broadcast:

a directed broadcast is a message to either the network number of the broadcast number of a network. This can be exploited to flood connections. By spoofing an address and sending a directed broadcast, all host belonging to a network, will reply. By disabling directed broadcast. The broadcast will not be translated to a physical broadcast. this means no hosts wil reply.

ip classless means the router will asume subnet masks according to the IP class of the IP number hense:

Class A

Class B

Class C

ip subnet-zero means the router can use the first subnet in the range.

If you subnet a class c network in four subnets

The ranges will be: - <--First subnet in range - - -

If NO ip subnet-zero is configured, the router cannot use the first subnet.

I don't know about fair-queue.. I'll have to look it up

Community Member

Re: question about ip commands -

thank you very much

Community Member

Re: question about ip commands -

It looks to me like the explanation above regarding ip classless really applies to classful routing. doesn't ip classless refer to vlsm?. Please correct me if I am confused.

Community Member

Re: question about ip commands -

I looked up the command in the IOS reference, this is what it said:

ip classless

At times the router might receive packets destined for a subnet of a network that has no network default route. To have the Cisco IOS software forward such packets to the best supernet route possible, use the ip classless global configuration command. To disable this feature, use the no form of this command.

Community Member

Re: question about ip commands -

Thanks for the above. On to the next question. Weighted fair queuing is enabled by default on interfaces with less than 2M and on interfaces that support it. To disable this function use no-faire queuing.

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