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openVPN with LZO-compression

Questions and discussions about the operating system RTOS and the corresponding C-LIB.

wie kann beim openVPN-Client die LZO-Komprimierung aktiviert werden?

Im Kommandozeilen-Konfigurationsfile habe ich den Eintrag "comp-lzo yes" stehen.

Beim Start meldet der Client dies auch:
OVPNdrv 00:00: LZO compression initialized

In der tun-Device-Aufzeichnung sind die Daten (ASCII-Textfile) jedoch unkomprimiert zu lesen.

Sind weitere Einstellungen notwendig?

Thomas Rebhan

Thomas Rebhan has provided the answer to this puzzle with the following additional information:

my vpn connection use the default cipher:
OVPNdrv 00:00: Static Decrypt: Cipher 'BF-CBC' initialized with 128 bit key
OVPNdrv 00:00: Static Decrypt: Using 160 bit message hash 'SHA1' for HMAC authentication

Comparison of the File sizes:
Testfile: 279213 Byte
WireShark capture-Files:

without LZO with LZO
LAN (IP 192.x) 307 kB 124 kB
VPN (IP 172.x) 292 kB 292 kB

The lzo compression has halved the traffic on the LAN side.
With the direct recording in the tunnel, however, no data reduction can be seen.
Does Wireshark automatically extract the compressed data?

When the OpenVPN tunnel network adapter is traced on a PC with WireShark, the decrypted and decompressed channel data will be seen there. This is after the OpenVPN program has done its job to recover the message from the encrypted LAN traffic.
Jack Gatrost
Software Development
Beck IPC GmbH

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