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Feature #10222

closed

Tune GRE MTU if GRE over IPsec is used

Added by Viktor Gurov almost 5 years ago. Updated almost 5 years ago.

Status:
Resolved
Priority:
Normal
Category:
Interfaces
Target version:
Start date:
01/30/2020
Due date:
% Done:

100%

Estimated time:
Plus Target Version:
Release Notes:

Description

Default GRE MTU value is 1500 (it should be 1476 as maximum for ethernet),
This is impossible in most cases when GRE/IPsec is used

It can be useful to set default MTU value for such cases to 1400
by using such logic:

if ((GRE SOURCE == IPSEC PH1 SOURCE) && (GRE DESTINATION == IPSEC PH2 DESTINATION) &&
    (IPSEC MODE == TRANSPORT) && (IPSEC == ENABLED) && (GRE MTU is not manually entered)) {
            $GRE_MTU = 1400;
}

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