[PATCH] Don't have ICMP Echo Replies copy fragmentation flags from Echo Request

[Mike Tancsa]

On 10/7/2011 11:54 AM, Ryan Stone wrote:
> Currently when FreeBSD responds to a ICMP Echo Request, it takes the
> original mbuf, rewrites a couple of fields (like the src/dst IP and
> the ICMP type), and then sends that mbuf back.  As things are
> currently implemented, the Don't Fragment bit is kept in the ICMP
> replay.  This can cause problems for large ICMP Echo Requests if the
> MTU on the return route is less than the MTU on the incoming route and
> the DF bit is set(Linux's ping command sets it by default).  

Not sure, but would this not be a "good thing" in some cases ? Having
ping behave in this manner would help you discover such PMTU issues no ?

	---Mike

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Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
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