Can't Connect To PPTP VPN With Ufw Enabled On Ubuntu 14.04 With Kernel 3.18
Answer : This is caused by a change for security reason in kernel 3.18 [1]. There are two ways to fix this. First approach is adding this rule to the file /etc/ufw/before.rules before the line # drop INVALID packets ... -A ufw-before-input -p 47 -j ACCEPT Second approach is manually loading the nf_conntrack_pptp module. You can do this by running sudo modprobe nf_conntrack_pptp To load this module on every boot on Ubuntu, add it to the file /etc/modules . For more recent versions of ufw a solution is instead: sudo ufw allow proto gre from [PPTP gateway IP address] sudo systemctl restart ufw Add nf_conntrack_pptp to /etc/modules-load.d/pptp.conf One liner echo nf_conntrack_pptp | sudo tee /etc/modules-load.d/pptp.conf Explanation The accepted answer works for me, especially the 2nd suggestion--loading the nf_conntrack_pptp kernel module--as opposed to modifying my iptables firewall. My laptop firewall is otherwise unmodified. sudo ufw enable without excepti...