routing difference between tun and tap

Need help configuring your VPN? Just post here and you'll get that help.
Forum rules
Please use the [oconf] BB tag for openvpn Configurations. See viewtopic.php?f=30&t=21589 for an example.
Post Reply
stmu86
OpenVpn Newbie
Posts: 1
Joined: Mon May 18, 2020 9:22 am

routing difference between tun and tap

Post by stmu86 » Mon May 18, 2020 9:45 am

hi guys

i despair with the following special vpn configuration.. [target network <-> client1<-> server <-> client2]
(client2 should be able to connect to the internal network of client1.)
first, if i take the tap adpater, everything works fine.

but if i switch to tun, the packets from client2 to the internal network of client1 don't arrive the client1 at 10.8.2.2.
a tcpdump on client1 tun0 shows nothing.
a tcpdump on the server shows the icmp request packets but no answer.

but server, client1 and client2 can ping each other.

server.conf

topology subnet
server 10.8.2.0 255.255.255.0


ccd-test-client1

ifconfig-push 10.8.2.2 255.255.255.0


ccd-test-client2

ifconfig-push 10.8.2.3 255.255.255.0
push "route 192.168.1.0 255.255.255.0"


routing and other setup:

Code: Select all

ip rule add from 10.8.2.3 table 1
ip route add 192.168.1.0/24 via 10.8.2.2 dev tun0 table 1
iptables -P FORWARD -j ACCEPT
echo 1 > /proc/sys/net/ipv4/ip_forward
on client1:

Code: Select all

iptables -P FORWARD -j ACCEPT
echo 1 > /proc/sys/net/ipv4/ip_forward
##iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to 192.168.1.1
whats wrong?
thanks.

Post Reply