Re: [Openvpn-users] What is the function of ipp.txt ?

[Josh C. <jos...@us...>]

Timothy Murphy wrote:
> William Maddler wrote:
>
>   
>> "ifconfig-pool-persist /etc/openvpn/ipp.txt: This makes OpenVPN keep a 
>> list of certificate to IP relationships, so that a client connecting 
>> will (probably) always have the same IP. "
>>     
>
> Here is my ipp.txt :
> --------------------------------------
> mary,192.168.5.4
> www.gayleard.com,192.168.5.8
> --------------------------------------
> Here is the relevant line in ifconfig on mary:
> --------------------------------------
> tun0      Link encap:UNSPEC  HWaddr 
> 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
>           inet addr:192.168.5.6  P-t-P:192.168.5.5  Mask:255.255.255.255
> --------------------------------------
> which seems to have nothing to do with the entry above.
> Similarly ifconfig on my server gives 2 tun0 IP addresses
> different to the one above.
>
> There is a 3rd machine - a remote client - 
> which has not had an entry made in ipp.txt .
>
> It doesn't really worry me -
> but I just don't see how these entries in ipp.txt
> can possibly help.
>   

The address shown on mary's line in the ipp.txt file is showing you the
starting IP of the virtual /30 subnet allocated to clients in "net30"
mode with tun (the default for a server/client setup.)  192.168.5.4/30
provides 2 usable peer IP's, .5 and .6 shown from your ifconfig output.

You might find a tool like sipcalc or ipcalc useful, which are command
line tools to show you network information; you can find some online
versions of these as well.  Here's some sample output that makes your
example easier to understand:

sipcalc 192.168.5.4/30 | grep range
Network range           - 192.168.5.4 - 192.168.5.7
Usable range            - 192.168.5.5 - 192.168.5.6

-- 
Josh