I have VPN server on Debian stable. People in LAN (gray network) use this server for access to internet (WAN). But I also want to use this VPN server as something like "proxy" (connect from internet, and browse the web). I can connect to server from internet, but internet not work: client get IP from server, also can ping other clients, but can't ping default gateway (which is server's IP address inside GRE tun). Adding default route to gateway doesn't help.
My PPTPD configuration:
─➤ grep -v '^$\|^\s*\#' /etc/pptpd.conf option /etc/ppp/pptpd-options logwtmp localip 192.168.4.1 remoteip 192.168.4.2-30 ─➤ grep -v '^$\|^\s*\#' pptpd-options name pptpd refuse-pap refuse-chap refuse-mschap require-mschap-v2 nodefaultroute debug lock nobsdcomp ─➤ sysctl -a | grep ip_forward net.ipv4.ip_forward = 1
iptables -t nat -I POSTROUTING -s 192.168.4.0/255.255.255.0 -j MASQUERADE iptables -I FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
In logs everything just fine: client connects, getting IP. Server also connecting to internet via ISP VPN servers.