TMS zl Management and Configuration Guide ST.1.1.100430

5-8
Network Address Translation
NAT Operations
The TMS zl Module will perform many-to-one destination NAT if you specify
multiple destination addresses, one NAT address, and no NAT port.
The source and destination IP addresses (SA, DA) and port fields (SP, DP) in
five inbound IP packet headers are shown in Table 5-5. The translated fields
are shown with shading.
Table 5-5. One-to-Many Destination NAT
Port Forwarding (for One-to-One or Many-to-One)
With this type of destination NAT, one public IP address translates to multiple
private destination IP addresses, each providing a different service. For
example, traffic sent to the public IP address 192.168.5.23 is translated to two
private destination IP addresses: 10.1.1.10, which provides HTTP (TCP port
80) services, and 10.1.1.11, which provides FTP (TCP port 21) services. The
destination IP address of the packet is translated to the correct private IP
address according to the destination port number of the incoming packet. For
example, a packet destined to 192.168.5.23 at port 80 is sent to the HTTP server
at 10.1.1.10.
The TMS zl Module will perform port forwarding if you create multiple
destination NAT policies with the same destination address, but different NAT
addresses and services. The example requires two destination NAT policies:
one to translate HTTP traffic and one to translate FTP traffic.
The source and destination IP address (SA, DA) and port fields (SP, DP) in five
inbound IP packet headers are shown in Table 5-6. The translated fields are
shown with shading.
Before NAT After NAT
SA
1
SP
1
DA
1
DP
1
SA
2
SP
2
DA
2
DP
2
172.16.122.63 51005 192.168.5.23 80 172.16.122.63 51005 10.1.1.10 80
10.1.5.48 50056 192.168.5.24 21 10.1.5.48 50056
10.1.1.10 21
10.100.148.77 50057 192.168.5.24 88 10.100.148.77 50057
10.1.1.10 88
172.20.222.8 50058 192.168.5.25 53 172.20.222.8 50058
10.1.1.10 53
172.25.121.75 50059 192.168.5.23 69 172.25.121.75 50059
10.1.1.10 69