MAC adress masqerade?

[ipupkin]

It's not about computers, it is about industrial devices (programmable logical controllers) using ethernet to communicate.

I have two "talkers" in two ethernet segments. They need to talk each to other, BUT THAY HAVE EQUAL MAC ADRESSES.

Is there a possibility to obtain switch smart enough to do "MAC adress masquerade":

[tt]
+--+
" Hello ...06.01.03"-->| |--->"Hello ...99.99.99"
"Hi, I'm ...06.01.03"<-| |<-"Hi, I'm ...99.99.99"
+--+

[/tt]

 

[franklin97355]

Not sure what you are asking. How did they get the same MAC addresses? Can you change them?Switches use IP not MAC to route (I think that's right)

 

[jimbopalmer]

MAC addresses are usually assigned by the hardware vendor, altough sometimes you can override a hardware MAC.

Switches are typically layer two devices and use MAC, not IP to send packets.

I tried to remain child-like, all I acheived was childish.

 

[ipupkin]

Thanks for replies!

Two "talkers" are inductrial programmable logical controllers. MAC adresses are assigned by programm developer - full flexibility. MACs were left "by default" (equal), because they are in different segments and nobody expected that these two must communicate each with other.

"talkers" do not use IP. they use own ethernet-based transport.

 

[AvayaNovice]

No... but you could put a device in front if it that can act like it's a different MAC adress, such as a small gateway router.

 

[jimbopalmer]

Routers are Layer 3 devices, we know it does not use IP as it's layer 3 protocol, perhaps it HAS no layer 3 protocol or perhaps that protocol is not routable. (LAT and NetBIOS are not routable)

I tried to remain child-like, all I acheived was childish.

 

[dearingkr]

If you use a hub to connect them, then MAC addresses are irrelevant.

A hub sends all traffic out all ports (one collision domain).

 

[BOKA]

Can you have one of the MACs changed?
I have seen Cisco 5500 doing MAC masquerading once, but I think it's an expensive solution if you do not have it in place already.
What happened here is one of our systems (not a computer) lost it's MAC - it's become ALL-ZEROS, so in the packet sniffer we saw MAC of 01-02-03-04-05-06 for this system. However, when same happened to another system on the same VLAN, the switch could not come up with another MAC and only one system was visible at any time. That how we found out we have an issue.

Good luck.