PMTU discovery question

[Gerald Breuer]

Is there a way to see a list for wich ip-addresses the path MTU
discovery has learned which MTU? I'm interested in Linux, Windows
and OS X.

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[Gerald Breuer]

Post by Gerald Breuer
Is there a way to see a list for wich ip-addresses the path MTU
discovery has learned which MTU? I'm interested in Linux, Windows
and OS X.

I got it at least for Windows:
netsh interface ipv4 show destinationcache


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[Rob Warnock]

Gerald Breuer <***@gmail.com> wrote:
+---------------
| schrieb Gerald Breuer:
| > Is there a way to see a list for wich ip-addresses the path MTU
| > discovery has learned which MTU? I'm interested in Linux, Windows
| > and OS X.
|
| I got it at least for Windows:
| netsh interface ipv4 show destinationcache
+---------------

For FreeBSD, it's "netstat -r" (show routes) with the
"-W" suboption added [and you probably want to add "-n"
as well to turn off reverse lookups of IPs, or it'll
be *sloooow*], that is:

netstat -rWn

Since OS X is partially based on FreeBSD, I'd suggest
trying that in a terminal (shell) window and see what
you get.


-Rob

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Rob Warnock <***@rpw3.org>
627 26th Avenue <http://rpw3.org/>
San Mateo, CA 94403

[Mike O'Connor]

Post by Rob Warnock
+---------------
| > Is there a way to see a list for wich ip-addresses the path MTU
| > discovery has learned which MTU? I'm interested in Linux, Windows
| > and OS X.
|
| netsh interface ipv4 show destinationcache
+---------------
For FreeBSD, it's "netstat -r" (show routes) with the
"-W" suboption added [and you probably want to add "-n"
as well to turn off reverse lookups of IPs, or it'll
netstat -rWn
Since OS X is partially based on FreeBSD, I'd suggest
trying that in a terminal (shell) window and see what
you get.

netstat -rl is what you want for OS X.

-Mike

[Jorgen Grahn]

Post by Gerald Breuer
Is there a way to see a list for wich ip-addresses the path MTU
discovery has learned which MTU? I'm interested in Linux, Windows
and OS X.

# route -neC

seems like a decent option for Linux and IPv4. The ip(8) command
probably has a way to display the information, too.

/Jorgen