Snat

Contents

These scenarios show how to configure SNAT (Source Network Address Translation) on OSDx.

Test SNAT

Description

In this scenario, DUT0 modifies the source address of outgoing packets generated at the LAN side. The address is translated to a custom one: 10.0.0.1.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 192.168.100.1/24
set interfaces ethernet eth1 address 10.0.0.2/24
set interfaces ethernet eth1 traffic nat source rule 1 address 10.0.0.2
set interfaces ethernet eth1 traffic nat source rule 1 selector SEL
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set traffic selector SEL rule 1 protocol tcp,udp

Step 2: Set the following configuration in DUT1:

set interfaces ethernet eth0 address 10.0.0.22/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2:

set interfaces ethernet eth0 address 192.168.100.2/24
set protocols static route 0.0.0.0/0 next-hop 192.168.100.1
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 4: Ping IP address 192.168.100.2 from DUT0:

admin@DUT0$ ping 192.168.100.2 count 1 size 56 timeout 1

Show output

PING 192.168.100.2 (192.168.100.2) 56(84) bytes of data.
64 bytes from 192.168.100.2: icmp_seq=1 ttl=64 time=0.324 ms

--- 192.168.100.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.324/0.324/0.324/0.000 ms

Step 5: Ping IP address 10.0.0.22 from DUT0:

admin@DUT0$ ping 10.0.0.22 count 1 size 56 timeout 1

Show output

PING 10.0.0.22 (10.0.0.22) 56(84) bytes of data.
64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.466 ms

--- 10.0.0.22 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.466/0.466/0.466/0.000 ms

Step 6: Initiate a tcp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 8080 tcp
admin@DUT2$ monitor test connection client 10.0.0.22 8080 tcp

Step 7: Initiate a udp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 5050 udp
admin@DUT2$ monitor test connection client 10.0.0.22 5050 udp

Step 8: Run command system conntrack show nat at DUT0 and check if output contains the following tokens:

src=192.168.100.2 dst=10.0.0.22
src=10.0.0.22 dst=10.0.0.2

Show output

icmp     1 24 src=192.168.100.1 dst=192.168.100.2 type=8 code=0 id=53 packets=1 bytes=84 src=192.168.100.2 dst=192.168.100.1 type=0 code=0 id=53 packets=1 bytes=84 mark=0 use=1
tcp      6 src=192.168.100.2 dst=10.0.0.22 sport=40546 dport=8080 packets=10 bytes=628 src=10.0.0.22 dst=10.0.0.2 sport=8080 dport=40546 packets=9 bytes=576 [ASSURED] [OFFLOAD, packets=6 bytes=412 packets=6 bytes=412] mark=0 use=2
icmp     1 24 src=10.0.0.2 dst=10.0.0.22 type=8 code=0 id=54 packets=1 bytes=84 src=10.0.0.22 dst=10.0.0.2 type=0 code=0 id=54 packets=1 bytes=84 mark=0 use=1
udp      17 src=192.168.100.2 dst=10.0.0.22 sport=34336 dport=5050 packets=5 bytes=240 src=10.0.0.22 dst=10.0.0.2 sport=5050 dport=34336 packets=5 bytes=240 [OFFLOAD, packets=3 bytes=144 packets=4 bytes=192] mark=0 use=2
conntrack v1.4.7 (conntrack-tools): 4 flow entries have been shown.

---

Test SNAT Masquerade

Description

This scenario is similar to the previous one, but when masquerade is specified, the route uses the IP address of the outgoing interface. Therefore, masquerading should be configured if the outgoing interface uses a dynamic IP address.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 192.168.100.1/24
set interfaces ethernet eth1 address 10.0.0.2/24
set interfaces ethernet eth1 traffic nat source rule 1 address masquerade
set interfaces ethernet eth1 traffic nat source rule 1 selector SEL
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set traffic selector SEL rule 1 protocol tcp,udp

Step 2: Set the following configuration in DUT1:

set interfaces ethernet eth0 address 10.0.0.22/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2:

set interfaces ethernet eth0 address 192.168.100.2/24
set protocols static route 0.0.0.0/0 next-hop 192.168.100.1
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 4: Ping IP address 192.168.100.2 from DUT0:

admin@DUT0$ ping 192.168.100.2 count 1 size 56 timeout 1

Show output

PING 192.168.100.2 (192.168.100.2) 56(84) bytes of data.
64 bytes from 192.168.100.2: icmp_seq=1 ttl=64 time=0.339 ms

--- 192.168.100.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.339/0.339/0.339/0.000 ms

Step 5: Ping IP address 10.0.0.22 from DUT0:

admin@DUT0$ ping 10.0.0.22 count 1 size 56 timeout 1

Show output

PING 10.0.0.22 (10.0.0.22) 56(84) bytes of data.
64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.309 ms

--- 10.0.0.22 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.309/0.309/0.309/0.000 ms

Step 6: Initiate a tcp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 8080 tcp
admin@DUT2$ monitor test connection client 10.0.0.22 8080 tcp

Step 7: Initiate a udp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 5050 udp
admin@DUT2$ monitor test connection client 10.0.0.22 5050 udp

Step 8: Run command system conntrack show nat at DUT0 and check if output contains the following tokens:

src=192.168.100.2 dst=10.0.0.22
src=10.0.0.22 dst=10.0.0.2

Show output

tcp      6 src=192.168.100.2 dst=10.0.0.22 sport=49738 dport=8080 packets=13 bytes=784 src=10.0.0.22 dst=10.0.0.2 sport=8080 dport=49738 packets=11 bytes=680 [ASSURED] [OFFLOAD, packets=9 bytes=568 packets=8 bytes=516] mark=0 use=2
icmp     1 24 src=192.168.100.1 dst=192.168.100.2 type=8 code=0 id=55 packets=1 bytes=84 src=192.168.100.2 dst=192.168.100.1 type=0 code=0 id=55 packets=1 bytes=84 mark=0 use=1
udp      17 src=192.168.100.2 dst=10.0.0.22 sport=47716 dport=5050 packets=5 bytes=240 src=10.0.0.22 dst=10.0.0.2 sport=5050 dport=47716 packets=5 bytes=240 [OFFLOAD, packets=3 bytes=144 packets=4 bytes=192] mark=0 use=2
icmp     1 24 src=10.0.0.2 dst=10.0.0.22 type=8 code=0 id=56 packets=1 bytes=84 src=10.0.0.22 dst=10.0.0.2 type=0 code=0 id=56 packets=1 bytes=84 mark=0 use=1
conntrack v1.4.7 (conntrack-tools): 4 flow entries have been shown.

---

Test SNAT Port Pool

Description

In this scenario, the translation is performed using masquerade with a pool of 3 ports. If at any time there are 3 active connections, the next one will be rejected.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 192.168.100.1/24
set interfaces ethernet eth1 address 10.0.0.2/24
set interfaces ethernet eth1 traffic nat source rule 1 address masquerade
set interfaces ethernet eth1 traffic nat source rule 1 port 1000-1003
set interfaces ethernet eth1 traffic nat source rule 1 protocol tcp
set interfaces ethernet eth1 traffic nat source rule 1 selector SEL
set interfaces ethernet eth1 traffic nat source rule 2 address masquerade
set interfaces ethernet eth1 traffic nat source rule 2 port 1000-1003
set interfaces ethernet eth1 traffic nat source rule 2 protocol udp
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set traffic selector SEL rule 1 protocol tcp,udp

Step 2: Set the following configuration in DUT1:

set interfaces ethernet eth0 address 10.0.0.22/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2:

set interfaces ethernet eth0 address 192.168.100.2/24
set protocols static route 0.0.0.0/0 next-hop 192.168.100.1
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 4: Ping IP address 192.168.100.2 from DUT0:

admin@DUT0$ ping 192.168.100.2 count 1 size 56 timeout 1

Show output

PING 192.168.100.2 (192.168.100.2) 56(84) bytes of data.
64 bytes from 192.168.100.2: icmp_seq=1 ttl=64 time=0.311 ms

--- 192.168.100.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.311/0.311/0.311/0.000 ms

Step 5: Ping IP address 10.0.0.22 from DUT0:

admin@DUT0$ ping 10.0.0.22 count 1 size 56 timeout 1

Show output

PING 10.0.0.22 (10.0.0.22) 56(84) bytes of data.
64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.347 ms

--- 10.0.0.22 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.347/0.347/0.347/0.000 ms

Step 6: Initiate a tcp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 8080 tcp
admin@DUT2$ monitor test connection client 10.0.0.22 8080 tcp

Step 7: Initiate a udp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 5050 udp
admin@DUT2$ monitor test connection client 10.0.0.22 5050 udp

Step 8: Run command system conntrack show nat at DUT0 and check if output contains the following tokens:

src=192.168.100.2 dst=10.0.0.22
src=10.0.0.22 dst=10.0.0.2

Show output

icmp     1 24 src=10.0.0.2 dst=10.0.0.22 type=8 code=0 id=58 packets=1 bytes=84 src=10.0.0.22 dst=10.0.0.2 type=0 code=0 id=58 packets=1 bytes=84 mark=0 use=1
icmp     1 24 src=192.168.100.1 dst=192.168.100.2 type=8 code=0 id=57 packets=1 bytes=84 src=192.168.100.2 dst=192.168.100.1 type=0 code=0 id=57 packets=1 bytes=84 mark=0 use=1
udp      17 src=192.168.100.2 dst=10.0.0.22 sport=46586 dport=5050 packets=5 bytes=240 src=10.0.0.22 dst=10.0.0.2 sport=5050 dport=1002 packets=5 bytes=240 [OFFLOAD, packets=3 bytes=144 packets=4 bytes=192] mark=0 use=2
tcp      6 src=192.168.100.2 dst=10.0.0.22 sport=55904 dport=8080 packets=10 bytes=628 src=10.0.0.22 dst=10.0.0.2 sport=8080 dport=1001 packets=9 bytes=576 [ASSURED] [OFFLOAD, packets=6 bytes=412 packets=6 bytes=412] mark=0 use=2
conntrack v1.4.7 (conntrack-tools): 4 flow entries have been shown.

---

Test SNAT Network Prefix

Description

In this scenario, the translation is performed using a network prefix. The host part of the original IP address is kept, but the network part is mangled using a subnet prefix.

Scenario

Step 1: Set the following configuration in DUT0:

set interfaces ethernet eth0 address 192.168.100.1/24
set interfaces ethernet eth1 address 10.0.0.2/24
set interfaces ethernet eth1 traffic nat source rule 1 network 10.0.0.0/24
set interfaces ethernet eth1 traffic nat source rule 1 selector SEL
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set traffic selector SEL rule 1 protocol tcp,udp

Step 2: Set the following configuration in DUT1:

set interfaces ethernet eth0 address 10.0.0.22/24
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Set the following configuration in DUT2:

set interfaces ethernet eth0 address 192.168.100.2/24
set protocols static route 0.0.0.0/0 next-hop 192.168.100.1
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 4: Ping IP address 192.168.100.2 from DUT0:

admin@DUT0$ ping 192.168.100.2 count 1 size 56 timeout 1

Show output

PING 192.168.100.2 (192.168.100.2) 56(84) bytes of data.
64 bytes from 192.168.100.2: icmp_seq=1 ttl=64 time=0.324 ms

--- 192.168.100.2 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.324/0.324/0.324/0.000 ms

Step 5: Ping IP address 10.0.0.22 from DUT0:

admin@DUT0$ ping 10.0.0.22 count 1 size 56 timeout 1

Show output

PING 10.0.0.22 (10.0.0.22) 56(84) bytes of data.
64 bytes from 10.0.0.22: icmp_seq=1 ttl=64 time=0.321 ms

--- 10.0.0.22 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.321/0.321/0.321/0.000 ms

Step 6: Initiate a tcp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 8080 tcp
admin@DUT2$ monitor test connection client 10.0.0.22 8080 tcp

Step 7: Initiate a udp connection from DUT2 to DUT1 and try to send some messages between both endpoints

admin@DUT1$ monitor test connection server 5050 udp
admin@DUT2$ monitor test connection client 10.0.0.22 5050 udp

Step 8: Run command system conntrack show nat at DUT0 and check if output contains the following tokens:

src=192.168.100.2 dst=10.0.0.22
src=10.0.0.22 dst=10.0.0.2

Show output

icmp     1 24 src=10.0.0.2 dst=10.0.0.22 type=8 code=0 id=60 packets=1 bytes=84 src=10.0.0.22 dst=10.0.0.2 type=0 code=0 id=60 packets=1 bytes=84 mark=0 use=1
tcp      6 src=192.168.100.2 dst=10.0.0.22 sport=50636 dport=8080 packets=10 bytes=628 src=10.0.0.22 dst=10.0.0.2 sport=8080 dport=50636 packets=9 bytes=576 [ASSURED] [OFFLOAD, packets=6 bytes=412 packets=6 bytes=412] mark=0 use=2
udp      17 src=192.168.100.2 dst=10.0.0.22 sport=56024 dport=5050 packets=5 bytes=240 src=10.0.0.22 dst=10.0.0.2 sport=5050 dport=56024 packets=5 bytes=240 [OFFLOAD, packets=3 bytes=144 packets=4 bytes=192] mark=0 use=2
icmp     1 24 src=192.168.100.1 dst=192.168.100.2 type=8 code=0 id=59 packets=1 bytes=84 src=192.168.100.2 dst=192.168.100.1 type=0 code=0 id=59 packets=1 bytes=84 mark=0 use=1
conntrack v1.4.7 (conntrack-tools): 4 flow entries have been shown.

---