Opened 2 years ago

Closed 2 years ago

#861 closed Bug / Defect (notabug)

OpenVPN 2.4 compression failure against 2.3 server

Reported by: worldcitizen Owned by:
Priority: major Milestone: release 2.4.0
Component: Configuration Version: OpenVPN 2.4.0 (Community Ed)
Severity: Not set (select this one, unless your'e a OpenVPN developer) Keywords: compression
Cc:

Description

When I connect to a 2.3.12 FreeBSD via 2.4.* Linux Client with this configuration:
client
dev tun
tun-ipv6
nobind
inactive 86400
comp-lzo no
<connection>
remote server port udp
</connection>
cipher AES-256-CBC
auth sha256
pkcs12 /<path>/file.p12
verify-x509-name server name
user nobody
persist-key
persist-tun

I see this warning if I connect to a IPv4 host:
Thu Mar 23 13:35:38 2017 UID set to nobody
Thu Mar 23 13:35:38 2017 Initialization Sequence Completed
Thu Mar 23 13:35:50 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:50 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:50 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:51 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:51 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:53 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:35:56 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:48 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:48 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:48 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:49 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:49 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:36:51 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:27 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:27 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:28 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:28 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:29 2017 Bad compression stub decompression header byte: 102
Thu Mar 23 13:37:30 2017 Bad compression stub decompression header byte: 102

If I connect via IPv6 I don't have any issue.

If I change option comp-lzo
For: comp-lzo no
To: comp-lzo yes

Everything is fine too, even tough the server has been configured, with:
comp-lzo no

This has been tested on openvpn 2.4.0 as well as openvpn 2.4.1

Change History (4)

comment:1 Changed 2 years ago by David Sommerseth

Component: Generic / unclassifiedConfiguration
Keywords: compression added
Summary: OpenVPN 2.4.* issueOpenVPN 2.4 compression failure against 2.3 server using IPv4

comment:2 Changed 2 years ago by Gert Döring

Summary: OpenVPN 2.4 compression failure against 2.3 server using IPv4OpenVPN 2.4 compression failure against 2.3 server

Well, this is the way it is. It's arguably a strange quirk in 2.3 that "comp-lzo no" is not actually turning *off* compression, but it turns compression *on* with the "stub" algorithm.

Not having "comp-lzo" *at all* in the 2.3 config would be the equivalent of "comp-lzo no" in 2.4 - so, just remove all traces of "comp-lzo" both in client and server config, or set it to "yes" on both sides.

IPv4 vs. IPv6 doesn't have anything to do with this.

comment:3 Changed 2 years ago by worldcitizen

Can be closed, was a config error.
Sorry.

comment:4 Changed 2 years ago by Gert Döring

Resolution: notabug
Status: newclosed
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