Catalyst 3750 - No default Gateway?

Unanswered Question
Mar 16th, 2010

I'm wondering about the pros & cons of not using a default-gateway on a Catalyst switch (3750E) being used as an IDF.  Switch has an IP, but just for remote management.  All L3 interfaces are on the core switch pair (using vrrp .1)

My peer engineer says we should, but I don't really see the benefit.  The switch is reachable without issue.  Should I add it or not?


I have this problem too.
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Leo Laohoo Tue, 03/16/2010 - 14:54

I've been deploying switches without default-gateway and they are all reachable.

Giuseppe Larosa Tue, 03/16/2010 - 15:22


to minimize ARP activity:

without an ip default-gateway the device relies on proxy-ARP enabled on L3 devices to find a way to send traffic to any destination.

It is sure that it should just answer to management workstations and to telnet/SSH sessions but if someone disables proxy-arp for security you will be not able to reach them.

I remember a similar case in a network when after some hardening there was a connectivity issue.

So I would deploy the ip default-gateway it costs just a config line.

Hope to help



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