User Manual

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Users Manual of XGS-6350-24X4C
Figure 43-3 Network Condition Where NAT Translates Overlapping Addresses
The routing switch performs the following steps when translating the overlapping addresses:
(1) The user of host 1.1.1.1 uses domain name to send instructions for connecting host C. Host 1.1.1.1
requires DNS server to perform a checkup from domain name to address.
(2) The DNS server responds the request and returns the address 1.1.1.1 of host C. The routing switch
intercepts the DNS response message and selects an outside local address from the outside local
address pool to replace the source address. In this case, the source address 1.1.1.1 is replaced with
address 3.3.3.3.
(3) The routing switch creates a mapping table about address transfer, where inside local addresses and
inside global addresses map each other, outside global address and outside local address map each
other.
(4) Host 1.1.1.1 sends message to host C . The destination IP address is the outside local address 3.3.3.3.
(5) When switch A receives message whose destination address is the outside local address, switch A
transfers the local address to the global address.
(6) Host C receives the packet and continues the session.
1. Configuring static transfer
Run the following commands in global configuration mode to configure static source address translation:
Run… To…
ip nat outside source static global-ip
local-ip
Creates static translation between outside
local address and outside global address.
interface type number
Specify the inside interface.
ip nat inside
Label the interface as one to connect the
inside network.
interfacetype number
Specify the outside interface.
ip nat outside
Label the interface as one to connect the