I took the material from how to understand the routing table on an OpenVPN client.

Here is the route table:

# route -n
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
10.8.0.5        0.0.0.0         255.255.255.255 UH    0      0        0 tun0
10.8.0.1        10.8.0.5        255.255.255.255 UGH   0      0        0 tun0
54.202.18.143   10.0.2.2        255.255.255.255 UGH   0      0        0 eth0
10.0.2.0        0.0.0.0         255.255.255.0   U     1      0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 eth0
0.0.0.0         10.8.0.5        128.0.0.0       UG    0      0        0 tun0
128.0.0.0       10.8.0.5        128.0.0.0       UG    0      0        0 tun0
0.0.0.0         10.0.2.2        0.0.0.0         UG    0      0        0 eth0

I configured the OpenVPN, and I am confusing about two things:

1. TCP packets via tun0
2. UDP OpenVPN packets via 54.202.18.143 (public VPN IP)

Question:

1. Why does OpenVPN need this line: 54.202.18.143 10.0.2.2 255.255.255.255 UGH 0 0 0 eth0?
2. Which packets are going through the tun0?
3. Which packets are going through the 54.202.18.143?

Thanks for your help!