I'm trying to run a PHP project on a test server.

The project uses an internal framework that has been modified so it will only run on the production server by checking the MAC address in eth0, and encoded with ioncube, (I have no access to the original source files, so I cannot modify the framework in any way, i only have the ioncube encoded files that were created about 10 years ago).

My server has 2 network interfaces (eth0 and eth1):

  • eth0 has the spoofed MAC address, and has no network cable connected.
  • eth1 has an IP (X.X.X.29) on the same network than the production server (X.X.X.30).

if I connect the computer to the same network as the production server, will be there a MAC Address conflict even though the spoofed MAC address is eth0 and not eth1?

As a precaution, I've always bringing down the eth0 interface before connecting to the local network, in order to connect to the internet.

My test server has CEntOS 6.7, while production has CEntOS 6.6.

  • Can you not just contact the vendor and get a trial/test license allocated to this MAC? – EEAA Oct 24 '15 at 20:36
  • Oh no, it's not a license, it is our own software that was encoded about 10 years ago, now the person who encoded has left and there are no copies of the original source around :/ I just got this project, and I'm trying to get it into versioning, so getting the original source code or allocation to other mac address is currently out of question. – Snivs Oct 26 '15 at 15:46
  • Ohh, I see. Yah, that's frustrating. :( – EEAA Oct 26 '15 at 16:06
  • Yeah, it's posing a challenge for my short experience, but I'll overcome it and learn a lot from it (with trusty SF and SO communities by my side, ha). – Snivs Oct 26 '15 at 16:10

Yes, some conflict could happend even if you forget disable eth0 or keep some ip on it. Because arp reply could go to another network. See http://linux-ip.net/html/ether-arp.html

For clean solution, enable arp_filter to prevent this on both server.

echo 1 > /proc/sys/net/ipv4/conf/all/arp_filter
  • Thanks for the info, after reading about arp in the link you provided, i got a doubt: Would ip link set arp off dev eth0 work in disabling arp just for eth0? eth0 is not intended to be connected to any network in this server, but I still want to be able to keep ARP on for eth1. – Snivs Oct 26 '15 at 16:09

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.