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connectlife
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Neighboring Routers send out a lot of Broadcast Requests

Wed Apr 27, 2022 6:52 pm

Hi guys, our network currently consists of 4 Mikrotik routers that communicate with each other via the OSPF protocol on a dedicated vlan. Another vlan is dedicated to WAN traffic
Yesterday we activated a VM with routerOS CHR which will serve as a transparent firewall for some virtual machines. we mapped the WAN interface (this VM will not have OSPF).
On the LOGs it appears:

ether2 excessive broadcasts / multicasts, probably a loop
ether2 is the WAN

doing a packet sniffer on ether2 the other 4 routers send us a lot of ARP packets:

Src. MAC Address: 00: 00: 5E: 00: 01: 0A
Dst. MAC Address: FF: FF: FF: FF: FF: FF
Protocol: 2054 (arp)

You can help me?
 
tdw
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Re: Neighboring Routers send out a lot of Broadcast Requests

Wed Apr 27, 2022 7:51 pm

00: 00: 5E: 00: 01: 0A is the MAC address for a VRRP interface with a VRID of 10, an interface with that address is trying to find an IP address with ARP.
 
connectlife
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Re: Neighboring Routers send out a lot of Broadcast Requests

Wed Apr 27, 2022 8:03 pm

Hi, yes, 2 routers have a VRRIP interface ..

But packets also come from physical interfaces and also from routers that do not have VRRIP, for convenience I have only reported 1 ...

The only thing that unites these 4 routers is the fact that I run OSPF .. On the network there is another Router (which does not run OSPF) and in fact it does not transmit anything (but always receives the ARPs from these 4 routers)

Src. MAC Address: 00: 50: 56: 24: CD: A3
Dst. MAC Address: FF: FF: FF: FF: FF: FF
Protocol: 2054 (arp)

Src. MAC Address: 2C: C8: 1B: B3: D9: 14
Dst. MAC Address: FF: FF: FF: FF: FF: FF
Protocol: 2054 (arp)

Src. MAC Address: 2C: C8: 1B: B3: E6: 8E
Dst. MAC Address: FF: FF: FF: FF: FF: FF
Protocol: 2054 (arp)
 
tdw
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Re: Neighboring Routers send out a lot of Broadcast Requests

Wed Apr 27, 2022 8:14 pm

What IP address are the ARPing for?
 
connectlife
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Re: Neighboring Routers send out a lot of Broadcast Requests

Wed Apr 27, 2022 8:34 pm

Image

I am attaching a screenshot of the packet sniffer

There is no IP on the source / dest

On torch I see:

806 (arp) src (empty) dst 0.0.0.0 with traffic of about 50kbps

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