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Bug #765

mtu of TUN is not set correctly on OS X

Added by Lian Duan almost 6 years ago. Updated over 2 years ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
osx
Target version:
-
Start date:
11.11.2014
Due date:
Estimated time:
Affected version:
5.2.1
Resolution:

Description

OS X client is using kernel-libipsec and tun device, but the TUN created by OS X client has a MTU of 1500, which is causing problems as websites like apple.com/speedtest.net has some problem with PMTU.

According to

src/libcharon/plugins/kernel_libipsec/kernel_libipsec_plugin.c

#define TUN_DEFAULT_MTU 1400

The default MTU should be 1400, but ifconfig clearly says

utun3: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
    inet 10.22.0.1 --> 10.22.0.1 netmask 0xff000000 

I suppose this is a bug in tun device implementation.

History

#2 Updated by Tobias Brunner over 2 years ago

  • Category set to osx

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