# Re: \[PATCH\] ipv4: icmp: Fix pMTU handling for rare case

- From: David Miller \<davem@davemloft.net\>
- Date: 2014-07-01 06:48:46 
- List: netdev
- Page: https://ratatoskr.run/netdev/2014/07/4284411
- Thread: https://ratatoskr.run/netdev/2014/06/4283950/t.md

```text
From: Edward Allcutt <redacted>
Date: Mon, 30 Jun 2014 16:16:02 +0100

> This is explicitly described as an eventuality that hosts must deal
> with by the standard (RFC 1191) since older standards specified that
> those bits must be zero.
 ...
> One example I have seen is an OpenBSD router terminating IPSec
> tunnels.

Why doesn't OpenBSD implement RFC 1191?

That's a nearly 24 year old standard.

I really don't want to allow for zero values.
```