I am trying to use pptp to connect to my company’s VPN but I found that SuSEfirewall2 blocks GRE packets from being received and prevents the VPN from working. How can I configure SuSEfirewall2 to permit GRE packets to pass through? I’m using networkmanager to do this. Note that if I disable SuSEfirewall2 that I can connect just fine, though this leaves me without the firewall protection. Ideally SuSEfirewall2 would automatically accommodate outgoing firewall requests.
I found the solution was to add “gre” to /etc/sysconfig/SuSEfirewall2 FW_EXT_SERVICES_IP.
For PPTP connectivity, it should only be necessary to make sure the necessary ‘connection tracking’ modules are loaded. Loading ‘nf_conntrack_pptp’ will result in the dependent modules (nf_conntrack and nf_conntrack_proto_gre) being loaded as well…
modprobe nf_conntrack_pptp
A recent thread…
https://forums.opensuse.org/showthread.php/525296-firewall-disables-VPN-how-to-have-both?p=2825923#post2825923