Re: [Openvpn-users] comp-lzo & push "comp-lzo"

[Erich T. <eri...@th...>]

Hi guys

at 16.09.2010 10:04, Jan Just Keijser wrote:
> Jason Haar wrote:
>>  On 09/16/2010 07:04 PM, Erich Titl wrote:
>>   
>>> From the fine manual ... First, make sure the client-side config file
>>> enables selective compression by having at least one --comp-lzo
>>> directive, such as --comp-lzo no. This will turn off compression by
>>> default, but allow a future directive push from the server to
>>> dynamically change the on/off/adaptive setting.
>>>     
>>
>> Urgh. You may be right - but it's certainly not intuitive. It makes no
>> sense that not mentioning a feature (comp-lzo) can make something crash...
>>
>> Either there should be a default setting for comp-lzo (I'd suggest
>> "adaptive" - more people would want compression than not), or openvpn
>> should error at startup if it's compiled with lzo support and there is
>> no mention of it in the config?
>>
>>   
> What worries me is that a server admin reads the manual and thinks "hey 
> I can just add 'comp-lzo' and 'push "comp-lzo"' and it will just work, 
> just like adding a route - and then the client can no longer connect 
> until the client config has 'comp-lzo [yes|no|adaptive]' added.
> The different compression and encryption options can be quite confusing. 
> I think a negotiation protocol would make more sense, e.g. the client 
> connects to the server and states

The thing that puzzled me all the time...

Could the compression not be a run time thing? Dynamically loading code
at runtime is definitely possible in Linux, I have heard that even
Windoze supports it. I doubt it would be impossible in BSC maybe in old
System5 based installations.

So Why not make it a default, but not loading the code at program load
but whenever either a default, push or explicit setting is seen (with a
reasonable fallback and some kind of negotiation.

something like

- <client> hi, I am an openvpn client supporting among others, compression
- <server> right, unfortunately I do not, I will log your settings but
let's just play without compression
- <client> what a pity, but whatever you say, let me just make a note in
my log
- <server> whatever suits you, let's start

cheers

Erich