Optimizing 870 Series IPSec

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Dec 4th, 2009
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I have an IPSec VPN between two 871's.  For some reason throughput through the VPN is much slower than throughput to internet sites.  Is this typical behavior or, are there some optimizations that need to be done.  The CPU usage on the routers is only 17% and memory usage is only 32%.  I have one DSL line on each side, both with static IP addresses.

Any help, suggestions or links would be appreciated.


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Herbert Baerten Tue, 12/08/2009 - 03:45
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One thing to try is

ip tcp adjust-mss 1300

(and if that helps, you can tweak the value - the optimal value is probably around 1400 - 1420, depending on what kind of VPN tunnel you have exactly)


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