This should be really simple, but I just cannot see how to achieve it..

I have an RH 7.2 (2.4.14) server appliance running at a clients premises with poptop VPN installed and working fine.
We need to restrict access into the VPN to a range of external IP addresses, e.g. 82.23.128.0/19 (all the authorised users have fixed IP addresses within this range). This is an urgent requirement as we getting connections into the network from employees that have left the company.

I would have expected a parameter somewhere similar to that in xinetd.conf: only_from.
However, poptop / pptpd does not appear to have any options to do this.
The server is running IP tables but I have very limited knowledge of this and would rather not mess with a working configuration.
I know that poptop / pptpd uses the script ip-up.local every time a new connection is initiated and maybe some commands could be put in there but I am not aware of the available variables or the correct syntax. ip-up.local currently contains some iptables commands.

Any help is greatly appreciated.
Many thanks and Regards to all.

how about deleting expired passwords/accounts ?

if poptop supports tcpwrap you could just use /etc/hosts.allow

Hi, Many thanks for your response..
The expired accounts and passwords are removed from the server as a matter of course. However, as the VPN uses a single username and password for all access, then there is still the ability to connect into the network and explore shares, etc.
I did not install this server but took over the limited support of it. As the VPN works and they have many remote users connecting into it, I do not want to change the authentication settings. Better and easier to just restrict the IP range allowed to access it I thought.
I not aware of what poptop supports or how it works, thats why I came here to ask the experts.
I would have thought that restricting access by IP range to a Linux system VPN service was a fundamental feature, yet I have googled for hours and found nothing specific.
There must be someone with knowledge of this. Please help.
Thank you.

Hi,
Im still looking for a solution to this problem..
Does anyone have any ideas how to achieve this ?
Many thanks.