3Com 3032 Configuration Manual page 360

356 C 21: C
HAPTER ONFIGURING
Troubleshooting NAT
Configuration
IP A
PPLICATION
The internal LAN of an enterprise can dial-up to access Internet by the
address translation.
I. Networking Requirement
The internal LAN of an enterprise can dial-up to access Internet through serial port
S0 by the address translation of the 3Com Router series.
II. Networking Diagram
Figure 133 NAT configuration case networking diagram 2
PC A
PC B
III. Configuration Procedure
1 Configure address access control list and dialer-list
[Router] acl 1
[Router-acl-1] rule permit source 10.110.10.0 0.0.0.255
[Router] dialer listen-rule 1 ip 10.110.10.0 255.255.255.0
2 Configure dial-up property for the interface
[Router-Serial0] physical-mode async
[Router-Serial0] link-protocol ppp
[Router-Serial0] ip address ppp-negotiate
[Router-Serial0] ppp pap local-user 169 password simple 169
[Router-Serial0] modem
[Router-Serial0] dialer enable-legacy
[Router-Serial0] dialer-group 1
[Router-Serial0] dialer number 169
3 Correlate the address translation list and the interface
[Router-Serial0] nat outbound 1 interface
4 Configure a default route to serial 0
[Router] ip route-static 0.0.0.0 0.0.0.0 serial 0
Fault 1: Address translation abnormal
Troubleshooting: Turn ON the debug switch for NAT, and refer to
in the command for specific operation. According to the Debug
debugging
information displayed on the router, initially locate the failure, and then use other
commands to check further. Observe the source address after translation carefully,
and make sure that it is the expected address. Otherwise, it is possible that the
configuration of address pool is wrong. Meanwhile, make sure that there is
routing to return to the address pool segment in the network to be accessed. Take
into consideration the influence of firewall and address list of the address
conversion itself on address conversion, and also route configuration.
Router
Modem
Internet
debugging nat