How to find the hardware (Mac) address of a connected telnet client ?

[Lothar Krueler]

Hi,
for unique documentation of telnet logins i have to determine the hardware address of the client who wants to login. Can anyone tell me a simple way for getting it? I think of a statement i could place in the profile.

Thanks in advance
Lothar

[Deshpande Prashant · Accepted solution]

Hi Lothar
If you run #arp -a command
it will show you the IP addresses and its mac addresses accesing the machine.

Thanks.
Prashant.

[MANOJ SRIVASTAVA]

Hi Lothar


Client who have logged in


who -T | grep "user name " | awk '{print $9}'


Manoj Srivastava

[harry d brown jr]

If the client is a PC running windoze, do this from the PC

arp -a

looking for their IP address

or

ipconfig /all

looking for the line with

Physical Address

on it

live free or die
harry

[Lothar Krueler]

Thanks for your fast responses.
The arp -a command works fine, the who -T does not return the mac address in my HP UX 11.11
:-)
Lothar

[Mike Botha]

arp -a will work great for machines connected to your local ip segment, but bear in mind that if there is a connection from a remote sytem (ie. remote network via a router) you will not be able to determine the mac address of the machine that is loging in.
That is because the router rewrites the layer 2 mac header

[Lothar Krueler]

Hi Michael,
thank you - i didn't know that. The main idea was disabling nodes from which i know the IP-addresses and i don't want them to login. If one of this nodes reallises this, he could change his IP-address and try again - so i thought of remembering and checking the mac-adress. Your response told me, that this is not efficient in WAN because i cannot be sure in getting the right mac-adress.
Do you know a better way preventing known nodes from login ?

P.S. sorry for my late reply, i noticed your response 10 min. ago

[Keely Jackson]

Hi Lother

Changing IP address won't change the mac address as the mac address is unique for every lan card.

Cheers
Keely

[Stefan Schulz]

Hi,

just a little sidenote regarding the MAC Adress.

It is unique for this nic, every vendor has its own range of MAC adresses.

But some nic drivers allow to overwrite this MAC adress. So allthough the original MAC adress is unique, it might be overwritten.

Regards Stefan