Why is VPN L2TP client not pinging from VPN L2TP server?

Question

Debian

Hello! There is L2TP-iP-Sec VPN. The VPN server has the address 172.16.0.5, there are several VPN clients - on Windows, on Debian, on Android. There are no problems with the client on Windows (172.16.0.12) - it pings from the server and back, also all client ports are available on the server. With a client on Debian (172.16.0.10) - the problem is that the client does not ping from the server and the client ports are not available from the server. And from the client the server responds.

Answer 1

Check the firewall configuration on the Debian client.

# iptables -L -v -n
# iptables -t nat -L -v -n
# iptables -t mangle -L -v -n

Answer 2

Yes, my firewall is generally disabled, i.e. no rules.

Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Any thoughts?)