how host knows the ip address of other host

charlesdaniel

Hi Team,

One doubt on a basic question!!.

We all know arp-which is to get the mac address for its known ip(another connected) address..

My question here is,how the host knows the IP address of that connected(directly or indirectly via router) host???..

Pls clarify..

vasyvasy

That's the role of RARP in a switched environment

charlesdaniel

How it will do RARP,since it doesnt know the MAC address?

before arp it doesnt know the MAC also

vasyvasy

Not sure I understand correctly your question, but here goes... if it doesn't know the MAC address of the IP, it asks the switch (here is RARP).
If the switch doesn't have the MAC address of the destination already learned, it broadcasts on every interface to learn this MAC address...

EdTheLad

charlesdaniel wrote: »

My question here is,how the host knows the IP address of that connected(directly or indirectly via router) host???..

You need to tell the host the ip address of the remote host. For example, ping x.x.x.x; telnet x.x.x.x; ftp x.x.x.x; or an application is configured to use a specific address, like your browser has a dns server ip address configured.

deth1k

Like Ed said, ask yourself why a PC would want to "talk" to another one? what's the reason? they'd rather be left alone doing their own thing
Without users input it's a "dumb" machine, so you tell it what to do by running SMB/NFS/Join AD etc with remote destination IP, and that's how it knows it.