Brian Mathis wrote:
On Dec 14, 2007 4:11 PM, Milton Calnek milton@calnek.com wrote:
Brian wrote:
On Dec 14, 2007, at 3:21 PM, Les Mikesell wrote:
Jerry Geis wrote:
I have a device on my network that is not DHCP and I dont know the IP address of it and it has not method of finding it or changing it unless you know the IP address (setable by browser). Is there a way on linux, based on MAC address, to get the IP of the unit?
You accumulate a table of mac<->ip assocations, but only after communicating with something. arp -a will show the current entries (which expire fairly quickly). You might ping everything in the network range, then look for the mac in the arp list.
to ping every address, check out broadcast pings here
http://www.macworld.com/article/53277/2006/10/pingfind.html (or google other how-to's)
The tool you want is fping. It's available from the rpmforge repository.
fping -ga 192.168.c.d/m arp -n | grep aa:bb:cc:dd:ee:ff
Now you may have two problems:
- The unknown device is not in your address space. ie: your net is
192.168.0.0/24 and the ip of the device is 192.168.1.1. 2. Your mask is too large. ie: 192.168.0.0/20 may be too large for you to scan the entire address space before your arp tables runs out of room.
Good luck.
-- Milton Calnek BSc, A/Slt(Ret.)
You can sacrifice a little bit of speed (this is not parallel) at the advantage of not having to install another package by doing something like this (using bash):
for ((i=1; i<=254; i+=1)) do ping -c 5 192.168.1.$i done
OR
for ((i=1; i<=254; i+=1)) do for ((j=1; j<=254; j+=1)) ping -c 5 192.168.$i.$j done done
You sacrifice a lot of speed. To the point where if you do your arp after all the pings have finished, some of the arp entries at the lower end will have been deleted based on time when working with one class C.
If you want to do it that way try: ping -c 3 192.168.$i.$j; arp -n | grep aa:bb:cc:dd:ee:ff
Also seq is much easier to use... for i in `seq 0 255`; do
You can probably get parallel by adding an "&" to the end of the ping line _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos