changing MAC on NIC hangs net service?!

[thedaver]

I wanted to change the MAC address on my small network as an experiment. On RedHat 7.3 I used the /etc/sysconfig/network-scripts/ifcfg-eth0 to add the new value
MACADDR=ab:bb:cb:db:eb:fb
and also tried
MACADDR=ab:bb:cb:db:eb

The MACADDR is successfully change in 'ifconfig eth0'.

Then I try 'ifdown eth0; ifup eth0', and 'service network restart'. The network connection from that new MAC doesn't allow anything but pings to leave the box.

I tried editing the IP address in the 'ifcfg-eth0' to another, ditinct IP to ensure that it wasn't some sort of ARP problem (which I understand very little). No help.

I have checked each ifconfig on the network for MAC conflict, there isn't one using the same MAC.

Why would a MAC change, even with full reboots of box, not allow traffic out except pings??? My egress router is a simple Cisco 1720 to a T-1, is it trying to do something "smart"???

Is there another settings to complement a MAC change?
Help please.


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[ady2k]

Your experiment was very interesting.
I know MAC address from each NIC is unique and integrated with the hardware setting.
You may try to exchange between two NIC MAC address and change the IP address too.
So you got other legal MAC address from another NIC.
This is cheating trick.....
Good Luck....

 

[thedaver]

I had expected to be able to change to ANY MAC of my choosing, not just under a particular vendor's sequence numbers.
Need more help.

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