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why need netmask

I found this mask in 4 case:

1.In route table,for windows,"route print" will have items like this:

destination mask gateway interface

2.when dialup pppoe,get an address with netmask

3.loopback interface of router can assign

an address with netmask

4.when setup ip alias,if the alias is in the same subnet,netmask must be

why does it need to be like this?

one more question,if there is a mathine have two ether interface,just as e1 and e2,set e1 as :,

then set e2 as :

when some other computers connect through

e2,which netmask should be set?

thx very much


Re: why need netmask

HI, [Pls Rate if HELPS]

The netmask means nothing but /32 address mask.

This /32 address mask is used in case-of Loopback Interface where it can be used as Router ID with Protocols / Management IP Address / any.

/32 means the single IP Address as VALID. In your case means only the above IP is valid and no more Network can be expanded with the segment.

Hope I am Informative.

Pls Rate if HELPS

Best Regards,

Guru Prasad R

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