Ethernet Switching
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Trusted Contributor
IOS2JunOS
Posts: 92
Registered: ‎10-17-2008
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Is there a JunOS command equivelent to "show mac-address-table address"?

to find a mac/host port?
Trusted Contributor
IOS2JunOS
Posts: 92
Registered: ‎10-17-2008

Re: Is there a JunOS command equivelent to "show mac-address-table address"?

found it "show ethernet-switching table brief" :smileyhappy:
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dambotkar@virtela.net
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Registered: ‎01-03-2011
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Re: Is there a JunOS command equivelent to "show mac-address-table address"?

Excellent!!!

Contributor
elboertjie
Posts: 29
Registered: ‎06-12-2014
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Re: 'show ethernet-switching table' type of command for an SRX?

What is the equivalent command on an SRX 5800 box?

 

The 'show ethernet-switching table' is not available on an SRX.

 

Thank you

Super Contributor
pantunes
Posts: 87
Registered: ‎01-25-2012
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Re: 'show ethernet-switching table' type of command for an SRX?

Try

 

 

show bridge mac-table 

 

 

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elboertjie
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Registered: ‎06-12-2014
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Re: 'show ethernet-switching table' type of command for an SRX?

Thanks for the response pantunes.

 

That command executes, but it shows no data at all.  The 'output' is completely empty.

 

How is it possible to not have MAC addresses on our Firewall?

 

The 'show arp' command reports mac/IP data, but this is only for devices that has had specific communication to them and not for devices that it listened to on the net.  The 'show ethernet-switching table' shows devices that it listened to on the network regardless if the devices had traffic sent to it or not.

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pantunes
Posts: 87
Registered: ‎01-25-2012
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Re: 'show ethernet-switching table' type of command for an SRX?

Hi,

 

 

But did you configure bridge domains on your SRX?

 

  • show arp shows how IP addresses are mapped with MAC addresses. So it is needed for layer 3.
  • show ethernet-switching table or show bridge mac-table (it depends of the platform you are using) will show MAC addresses learnt by layer 2 mechanisms. It means that the device is running as a switch on some interfaces.

 

 

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Contributor
elboertjie
Posts: 29
Registered: ‎06-12-2014
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Re: 'show ethernet-switching table' type of command for an SRX?

There are no bridge domains configured on our SRX.

 

So, is the 'show arp' the only way on an SRX to find out MAC addresses on the connected interfaces?

 

'show arp' is not complete - as you probably know - since it only shows MAC addresses for communication that already happened as opposed to devices quietly sitting on the network.

 

It will be odd if there is no sure way on an SRX to see MAC addresses of all devices, communicated to or not.

Super Contributor
pantunes
Posts: 87
Registered: ‎01-25-2012
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Re: 'show ethernet-switching table' type of command for an SRX?

 

 

If a device hasn't yet "communicated" there is no way to know its MAC.

 

 

 

Contributor
elboertjie
Posts: 29
Registered: ‎06-12-2014
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Re: 'show ethernet-switching table' type of command for an SRX?

Our EX device has 222 unique MAC addresses in the 'show ethernet-switching table' output whereas the 'show arp' command shows only 32 MAC addresses.

 

Why is that?

 

To my understanding, the 'show arp' only reports devices where 'communication' was sent to, such as a ping, ssh, http or some other direct traffic towards the device.  Also to my understanding, the 'show ethernet-switching table' shows all devices that shares a LAN with the local device (EX in this case), regardless if traffic was passed onto it or not.

 

Now for an SRX device, the 'show ethernet-switching table' does not exist, so how can I see all the MAC addresses that shares LAN(s) with the SRX device?

 

Our SRX box is a firewall, and since a lot of traffic passes over it, its 'show arp' output is large due to returning packets containing the MAC addresses in it, even if the device is two hops away and not locally attached on a LAN.

 

So, how can I see all the MAC addresses of devices that reside on LAN(s) that sit right next to our SRX device?

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