Junos OS

Every time that I deactivate / reactivate interface ae0 the mac address changes.

I think now juniper doesn't pre create the interface and assigns then ext mac from the pool. I see in the following article the new way:

https://kb.juniper.net/InfoCenter/index?page=content&id=KB32165&pmv=print&actp=RSS&searchid=&type=currentpaging

But since the remote end validates my mac address I need a permament mac address for ae0 that never changes.

I could use the command:

set interfaces ae0 mac xx:xx:xx:xx:xx:xx

But I prefer a real mac address since xx:xx:xx:xx:xx:xx would be a fake make address unless I know a way to choose a mac from juniper pool that not conflicts with whatever new interface created. Now for example junos assigns my previus ae0 mac address for jsrv interface.

Is there any solution for this?

Hello,

This should be fixed in JUNOS 16.1R4 and later -  PR 1202133.

HTH

Thx
Alex

For 18.x series do you know the version will be fixed?

If I understand for PR1202133 the way is to use set interface aeX mac <> . But how to choose a mac from private or public pool that will not cause conflict with other juniper interfaces?

Hello,

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@hugleo wrote:

 how to choose a mac from private or public pool that will not cause conflict with other juniper interfaces?

 

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IEEE  private MAC address pool is 46-bit wide (for private unicast MACs, only two bits are fixed - b1 in octet1, must be 1; and b0 in octet1, must be 0) so if You could come up with a scheme that does not start from 02:00:00:00:00:00 upwards, or better does not use 02: addresses at all, then the possibility of collision is diminished.

Example being:

1/ start from random first 6 bits, say, 49 decimal, binary b1100 01, append b10, arrive at b11000110, 0xc6 in hex

2/ convert the interface IP address to hex: 203.0.113.1 becomes CB:00:71:01

3/ append together [1] and [2] - C6:CB:00:71:01

4/ pad with Your chosen hex char, say, F - C6:CB:00:71:01:FF

HTH

Thx

Alex

That's mean that I can't use a juniper mac address range right?

show chassis mac-addresses

Public base address xx:xx:xx:31:18:0c
Public count 2032
Private base address xx:xx:xx:31:1f:fc
Private count 16

Would be good if I could use mac from my device range starting with xx:xx:xx:31. So mac vendor will be juniper.

But since is not possible I can use a mac address using your sugestion or use a mac address of one of my others devices that are in different network.

Hello,

---

@hugleo wrote:

That's mean that I can't use a juniper mac address range right?

 No it does not mean it.

You can use any unicast MAC if You want to - JUNOS CLI does not restrict this.

Best practice is to use private MACs to avoid interfering with other vendors' MAC ranges.

HTH

Thx
Alex

Hello,

JUNOS 18.x does not contain this bug, it was fixed way before 18.1 release branching.

HTh

Thx
Alex