sysctl config for ip packet forwarding

vpn.conf

# ipv4
net.ipv4.ip_forward=1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.icmp_ignore_bogus_error_responses = 1

# ipv6
net.ipv6.conf.all.send_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_source_route = 0
net.ipv6.conf.default.send_redirects = 0

# Enabling this option disables Stateless Address Autoconfiguration
# based on Router Advertisements for this host
net.ipv6.conf.all.forwarding=1