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zakynthoswifi
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Strange Network Loop

Thu Aug 08, 2019 4:29 pm

Hello,
today here in zakynthos we had an power outage and after that one of my customers routerboard gets this error.
if the port is damaged by a thunder is this a normal error or something else is happening?
I was getting this error again in the past but with a reboot os pord disabling and re-enabling it was fine!
the picture is after reboot so you will not see so many errors only two.
Also i can see strange things into my neighbour list.
loop.png
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Ilias Theodosis
Network & Security Engineer
Cisco CCNA,CCNP,CCIE
Network Solutions Ltd.
Zakynthos, Greece
 
sindy
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Re: Strange Network Loop

Thu Aug 08, 2019 6:47 pm

Given that the "MELI" and "MikroTik" devices are visible as neighbors at two interfaces each, and as these interfaces are probably member ports of the same bridge, the loop may actually be there, but you've provided too little information. So a configuration export (see my automatic signature below for an anonymisation hint) of all three devices as well as a diagram of the network interconnections is necessary to find out what has happened.

I can imagine that there is an interconnection Yameli-GW <-> MELI <-> MikroTik <-> Yameli-GW again, so if no L2 loop prevention protocol is running there, there is no wonder that the frames sent from the bridge return back to it.
Instead of writing novels, post /export hide-sensitive. Use find&replace in your favourite text editor to systematically replace all occurrences of each public IP address potentially identifying you by a distinctive pattern such as my.public.ip.1.
 
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ingdaka
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Re: Strange Network Loop

Sat Aug 10, 2019 11:19 pm

As Sindy has told you! Simple way there is a problem with cables!
Image
https://ibb.co/sHQjpLh

Also as I see there is the same MAC of Mikrotik know from port 2 and 3! Maybe there is a cable Loop too!
Ilir Daka
Electronic & Network Engineer
E-mail: ilirdaka@live.com
Mob: +355692982151
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Mikrotik Official Consultant
CCNA | Fortinet NSE3 | MTCRE | MTCSE

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