what holds your ip or whatever

[c44151]

ip adress
mac adress
or whatever
every computer has a diffrent something that stays the same from the day you get it to the day it dies right like an ip adress (xxx.xxx.xxx.123)something that tells the computers apart. now what I was wondering is what holds all that information.

[John Prophet]

you are thinking of the "MAC" address...or "media access control" #.

That is a number that is built into every Network card (NIC)ever built....so every NIC has its own unique MAC address.


one way to find your NICs MAC is to go to a dos prompt and type in "ipconfig /all"...it will be the "physical address"....usually written in "hexadecimal" fashoin, like 00-0b-E7-30-db-0e ......but its actually a 48 bit binary number...like 0011-0011-0011-0011-0011-1100-0101-0110-1110-0100-0110-0110

Ip addresses can change...but the MAC stays the same until you change the nic...(or unless you have a router or something that uses "mac emulation" to fake out your ISP, lol)

[bailey]

the mac address is set by the mfg of the device and placed it its own bios chip, nic, modems,routers and web cams all have a built-in mac address, your isp will assign this mac address as you IP address, this is also done by a DCHP server.

[DVNT1]

Originally posted by bailey
the mac address is set by the mfg of the device and placed it its own bios chip, nic, modems,routers and web cams all have a built-in mac address, your isp will assign this mac address as you IP address, this is also done by a DCHP server.

As written, that sounds misleading. The ISP does not assign your MAC address as the IP address. It assigns your computer an IP address and records your NIC's MAC address as an association.
The MAC address generally isn't seen outside of the local subnet, only the IP address is. Even though NICs are thought to have 100% unique MAC addresses, you and I could have the same MAC address and everything would still work perfectly. In relation, I understand manufacturers do/have reused MAC addresses but ensure they are shipped to different geographical regions.

[John Prophet]

Hey DVNT1..I was sitting here trying to remember a command to see the mac addresses on the network......is it a version of the "arp" command? Im sure its just a switch but I dont wanna play around with it and add something to a host file by accident, lol.

Uhh, I guess arp is used more for static type stuff as opposed to dhcp huh? Cuz i see I have no arp entries etc

[DVNT1]

arp -a will display the ARP table which shows MAC that your computer knows (on the local segment).

To get more MAC addresses in the table, try pinging or otherwise access shares on other computers, then run that command again.

For ARP tables, it doesn't matter if theother computers have Dynamic or static IP addesses.

[John Prophet]

but it doesnt show its own mac huh? Cuz I am getting no entries...(the other comps are off right now)

hehe, nevermind..that time it did show its own MAC with arp -a

[bailey]

Originally posted by DVNT1
As written, that sounds misleading. The ISP does not assign your MAC address as the IP address. It assigns your computer an IP address and records your NIC's MAC address as an association.
The MAC address generally isn't seen outside of the local subnet, only the IP address is. Even though NICs are thought to have 100% unique MAC addresses, you and I could have the same MAC address and everything would still work perfectly. In relation, I understand manufacturers do/have reused MAC addresses but ensure they are shipped to different geographical regions.

yea, I see what you mean, I should have worded it differant
LOL