icmp performance vs. traceroute/tcptraceroute, ssh, ipsec

Joe Maimon jmaimon at
Mon May 7 18:05:17 UTC 2007

Jo Rhett wrote:

> On May 6, 2007, at 6:07 PM, Joe Maimon wrote:
>> Of course, and thats why I have cut down ip mtu and tcp adjust mss  
>> and all the rest.
>> Not making much of a difference.
> Um.. sorry if you mean more than you said, but where did you cut down  
> the TCP MTU?   If you did it on your routers, then you are creating  or 
> at least complementing the problem.

On the CPE dialer interface.

On the ezvpn dvti virtual-template

> The only way to make smaller MTUs work is to alter the MTU on both  the 
> origin and destination systems.  Altering the MTU anywhere along  the 
> path only breaks things.

Lower than 1500 mtu always requires some kind of hack in real life.

That would be the adjust-mss which is the hack-of-choice

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