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MikroTik App
 
LdB
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Two mikrotik can't ping

Tue Aug 09, 2022 9:06 am

I have the weirdest problem on something I have done many many times

I have 2 mikrotiks connected by 5XHD ubiquiti link and weirdly they can't ping each other
I even reset the config on both so no firewalls on either
One tik is 192.168.21.1/24 the other is 192.168.21.2/24 the IPs are simply on the ethernet port
tik 1 ===> /interface address add address=192.168.21.1/24 interface=ether5
tik 2 ===> /interface address add address=192.168.21.2/24 interface=ether5
I even set the Radio management up inband on 192.168.21.3/24 and 192.168.21.4/24

Now the weird parts
1.) both tiks can ping the two radios but neither can ping each other
2.) I can mac telnet from one tik to the other
3.) When I go to neighbors the wrong MAC address is showing on the connected tik

I am completely stumped ... weirdest thing ever.
 
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bpwl
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 10:53 am

When I go to neighbors the wrong MAC address is showing on the connected tik
What is the meaning of wrong here? Mikrotik has one different MAC per interface.

If Ubiquiti link is set up as normal wifi 3-addressmode ,it will inject its own MAC address.
(4-address is special: like bridge mode in MT)
 
LdB
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 12:16 pm

@bpwl Look at the neighbors screen it shows each device mac and it's IP .. it was wrong for the 2nd CCR it isn't what it showed it was actual the other tiks MAC

Anyhow tried replacing each tik with a different one and when I replace the second one it worked.
The neighbors screen now correctly shows the other TIK mac an IP and I can ping and Telnet to it
Put that unit back in and problem comes back.

So one of the tiks has a weird problem it appears to be okay until it gets another tik as neighbor then all hell breaks loose.
What I probably should have done is turned the neighbour discovery off but I ran out of time.

Not sure what to do with the weird tik, guess I will bin it.
 
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bpwl
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 12:47 pm

@bpwl Look at the neighbors screen
Sorry don't see any screenshot, and there is no config file ("/export file=tik1", "/export file=tik2") either.

It can be anything, like giving 2 IP addresses to a tik. Or using duplicate MAC address in your network (e.g. by restoring backup of tik1 on tik2)
 
holvoetn
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 3:40 pm

Or using duplicate MAC address in your network (e.g. by restoring backup of tik1 on tik2)
A very likely candidate ...
 
LdB
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 6:26 pm

Ah that is it ... I had indeed restored the config of tik1 on tik2 before clearing tik2.

So I take it from that the MAC is software based and part of the config?
Talk about a gotcha :-)

So how do I clear it to get a unique MAC?
 
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bpwl
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Re: Two mikrotik can't ping

Tue Aug 09, 2022 7:31 pm

There is a difference between "config" (export and import), and backup (backup and restore)
Backup contains much more than the configuration, some things are device specific.
Moving configurations is with export/import (after removing the MAC addresses in the *.rsc file)

Every ethernet interface has the option "Reset MAC Address". WLAN interfaces have "Reset configuration".
The bridge normally takes the MAC address of the first active port connected to it. The management MAC address can be set to a static value.

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