I think you should better use &Network::equals() from
/var/ipfire/network-functions.pl. This will take care of converting
subnet masks to prefix notation and vice-versa.

Best,
-Michael

On Sun, 2018-02-11 at 19:51 +0100, Bernhard Held wrote:
> The logic of subnet comparison is broken. E.g. if the blue netmask is
> 255.255.255.0, it's impossible to add a VPN subnet with the same netmask.
> The proposed patch compares the subnets individually.
> ---
>  html/cgi-bin/proxy.cgi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/html/cgi-bin/proxy.cgi b/html/cgi-bin/proxy.cgi
> index ea3b41126..4993dde86 100644
> --- a/html/cgi-bin/proxy.cgi
> +++ b/html/cgi-bin/proxy.cgi
> @@ -3066,8 +3066,8 @@ END
>  				@temp = split(/\//);
>  				chomp $temp[1];
>  				if (
> -					($temp[0] ne $netsettings{'GREEN_NETADDRESS'}) && ($temp[1] ne $netsettings{'GREEN_NETMASK'}) &&
> -					($temp[0] ne $netsettings{'BLUE_NETADDRESS'}) && ($temp[1] ne $netsettings{'BLUE_NETMASK'})
> +					(($temp[0] ne $netsettings{'GREEN_NETADDRESS'}) || ($temp[1] ne $netsettings{'GREEN_NETMASK'})) &&
> +					(($temp[0] ne $netsettings{'BLUE_NETADDRESS'}) || ($temp[1] ne $netsettings{'BLUE_NETMASK'}))
>  					)
>  				{
>  					print FILE " ||\n     (isInNet(myIpAddress(), \"$temp[0]\", \"$temp[1]\"))";