[j-nsp] Etherchannel Cisco - Juniper and firewall filter

Valentini, Lucio Lucio.Valentini at siag.it
Fri Sep 9 10:36:46 EDT 2016


Hi there,

I  have a Juniper EX4200 connected through an etherchannel with a Cisco C3750; I noticed (with the "monitor traffic interface ae1" command)
the interface on the Juniper was receiving EIGRP Hello packets,  I applied this filter on the input in order to stop/drop these packets, because as far as I know there is no EIGRP-speaking router on the other side of the Juniper switch.

set firewall family ethernet-switching filter block-Eigrp term block-Eigrp from destination-mac-address 01:00:5e:00:00:0a/48
set firewall family ethernet-switching filter block-Eigrp term block-Eigrp then discard
set firewall family ethernet-switching filter block-Eigrp term block-Eigrp then count eigrp-count
set firewall family ethernet-switching filter block-Eigrp term traffic-allow then accept

information was taken from: https://kb.juniper.net/InfoCenter/index?page=content&id=KB14893&actp=search

where they say that the  mac-address 01:00:5e:00:00:0a/48 is used by EIGRP.

But instead of dropping only the EIGRP packets, the filter dropped traffic as well and the result was really bad.

Strangely enough, I tried to replicate the problem in the lab: I connected a Cisco router´s EIGRP Hello-generating interface to an EX4200, configured the IP addresses and the ping worked fine both ways.

Any ideas about how to drop only Hello packets without causing disruption ?
Thanks

Cheers

Lucio




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