Is there a built in tool to discover the path MTU?
If not, has anyone written a script to do it?
(At present I do it manually by doing /ping <ip> do-not-fragment count=1 size=1500 then decrementing size until I see a ping returned)
Chris
Re: Path MTU discovery
https://www.iea-software.com/products/mtupath/
MTU Path is a utility to assist operators in troubleshooting MTU related network configuration problems by finding the largest one-way path MTU (PMTU) to a remote host or router.
The software works by sending a small number of messages toward a host analyzing feedback from host and intermediate routers to determine largest packet size the network path will accept.
MTU Path is a utility to assist operators in troubleshooting MTU related network configuration problems by finding the largest one-way path MTU (PMTU) to a remote host or router.
The software works by sending a small number of messages toward a host analyzing feedback from host and intermediate routers to determine largest packet size the network path will accept.
Re: Path MTU discovery
That's great, but I want to do it on the router itself.
Wrote a script...
There might be a simpler way of doing it, but if not I hope it is useful to someone.
Chris
Wrote a script...
Code: Select all
:local yes
:local no
:local test
#Set upper and lower test limits below
:set yes 1000
:set no 1550
while (($no-$yes) > 1) do={
:set test (($no-$yes)/2 + $yes)
if ([/ping **YOUR TEST IP HERE** do-not-fragment count=1 size=$test] = 1) do={ :set yes $test } else={ :set no $test }
}
:put $yes
Chris