Topology
{F12380669}
Configuration commands:
```
set interfaces ethernet eth0 address 192.168.122.210/24
set interfaces ethernet eth1 address 100.64.0.1/24
set interfaces ethernet eth2 address '200.64.0.1/24'
set protocols static route 0.0.0.0/0 next-hop 192.168.122.1
set vpp settings lcp ignore-kernel-routes
set vpp settings interface eth0 driver 'dpdk'
set vpp settings interface eth1 driver 'dpdk'
set vpp settings interface eth2 driver 'dpdk'
set vpp settings unix poll-sleep-usec '122'
```
Additional VPP commands:
```
vyos@vyos:~$ sudo vppctl
_______ _ _ _____ ___
__/ __/ _ \ (_)__ | | / / _ \/ _ \
_/ _// // / / / _ \ | |/ / ___/ ___/
/_/ /____(_)_/\___/ |___/_/ /_/
vpp# nat44 plugin enable
vpp# nat44 forwarding enable
vpp# set interface nat44 out eth0 output-feature
vpp# set interface nat44 in eth1
vpp# nat44 add address 192.168.122.55 192.168.122.56
vpp# show nat44 interfaces
NAT44 interfaces:
eth1 in
eth0 output-feature in out
vpp# show nat44 sessions
NAT44 ED sessions:
-------- thread 0 vpp_main: 2 sessions --------
i2o 100.64.0.10 proto ICMP port 31987 fib 0
o2i 192.168.122.56 proto ICMP port 31987 fib 0
external host 1.1.1.1:31987
i2o flow: match: saddr 100.64.0.10 sport 31987 daddr 1.1.1.1 dport 31987 proto ICMP fib_idx 0 rewrite: saddr 192.168.122.56 daddr 1.1.1.1 icmp-id 31987 txfib 0
o2i flow: match: saddr 1.1.1.1 sport 31987 daddr 192.168.122.56 dport 31987 proto ICMP fib_idx 0 rewrite: saddr 1.1.1.1 daddr 100.64.0.10 icmp-id 31987 txfib 0
index 0
last heard 282.35
timeout in 59.23
total pkts 104, total bytes 8750
dynamic translation
i2o 200.64.0.10 proto ICMP port 44080 fib 0
o2i 192.168.122.56 proto ICMP port 44080 fib 0
external host 8.8.8.8:44080
i2o flow: match: saddr 200.64.0.10 sport 44080 daddr 8.8.8.8 dport 44080 proto ICMP fib_idx 0 rewrite: saddr 192.168.122.56 daddr 8.8.8.8 icmp-id 44080 txfib 0
o2i flow: match: saddr 8.8.8.8 sport 44080 daddr 192.168.122.56 dport 44080 proto ICMP fib_idx 0 rewrite: saddr 8.8.8.8 daddr 200.64.0.10 icmp-id 44080 txfib 0
index 1
last heard 282.69
timeout in 59.57
total pkts 104, total bytes 9464
dynamic translation
```
We cannot nat specific local interface traffic even if `in` interface is set
**One more issue**:
`in` and `out` interface is set without output-feature:
Vpp commands
```
vpp# set interface nat44 in eth1
vpp# set interface nat44 out eth0
vpp# show nat44 interfaces
NAT44 interfaces:
eth1 in
eth0 out
```
We cannot ping from Client-2 (as expected)
But when stop pings from Client-1 and then start pinging again it doesnt work
```
64 bytes from 1.1.1.1: icmp_seq=4125 ttl=126 time=7.26 ms
64 bytes from 1.1.1.1: icmp_seq=4126 ttl=126 time=6.65 ms
64 bytes from 1.1.1.1: icmp_seq=4127 ttl=126 time=7.38 ms
64 bytes from 1.1.1.1: icmp_seq=4128 ttl=126 time=7.31 ms
64 bytes from 1.1.1.1: icmp_seq=4129 ttl=126 time=7.19 ms
64 bytes from 1.1.1.1: icmp_seq=4130 ttl=126 time=7.39 ms
^C
--- 1.1.1.1 ping statistics ---
4130 packets transmitted, 2589 received, 37.3123% packet loss, time 4171678ms
rtt min/avg/max/mdev = 5.113/9.117/125.106/6.373 ms
vyos@vyos:~$ ping 1.1.1.1
PING 1.1.1.1 (1.1.1.1) 56(84) bytes of data.
```
The same with VPP API help in Python:
```
from vyos.vpp import VPPControl
vpp = VPPControl()
vpp.api.nat44_ed_plugin_enable_disable(enable=True) # enable nat44 plugin
vpp.api.nat44_forwarding_enable_disable(enable=True) # enable forwarding
vpp.api.nat44_ed_add_del_output_interface(sw_if_index=1, is_add=True) # enable output-feature on eth0 (outbound interface)
vpp.api.nat44_interface_add_del_feature(flags=0x20, sw_if_index=2, is_add=True) # set inbound interface eth1
vpp.api.nat44_add_del_address_range(first_ip_address='192.168.122.55', last_ip_address='192.168.122.56', is_add=True) # set translation pool
# vpp.api.nat44_interface_add_del_feature(flags=0x10, sw_if_index=1, is_add=True) # set outbound interface eth0 - for the second case
```