Tag Archives | ARP


War Stories: Gratuitous ARP and VRRP

Continuing our theme of ARP-related war stories, here’s another ARP/switching behaviour I’ve come across. This particular problem didn’t result in any outages, but the network wasn’t working as well as it should have, and started flooding frames unexpectedly. Here’s what was going on: The Network Breaking the network down to its simplest level, it looked like this: The […]

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Legacy Connection - No NAT needed

Proxy ARP Sucks

Proxy ARP was often used in network designs 10–15 years ago, to enable NAT. It helped get around some specific challenges, but it was always an administrative hassle, and caused significant scaling issues. There’s very little reason to use it these days, but sadly it still lingers on, just waiting to catch out junior engineers. […]

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