Troubleshooting Nat; Symptom 1: Abnormal Translation Of Ip Addresses; Symptom 2: Internal Server Functions Abnormally - 3Com MSR 50 Series Configuration Manual

Troubleshooting NAT

Symptom 1: Abnormal
Translation of IP
Addresses
Symptom 2: Internal
Server Functions
Abnormally
Network diagram
Figure 531 Export NAT log to log server
192.168 .1.5/24
Host
192.168.1.6/24
Configuration procedure
n
The following only lists configurations pertinent to NAT logs. Configurations
regarding the IP addresses of the devices and NAT function are omitted here.
# Specify to export the NAT logs of Device A to the NAT log server.
<DeviceA> system-view
[DeviceA] userlog nat export host 3.3.3.7 9021
# Set the source IP address of NAT log packets for Device A to 9.9.9.9
[DeviceA] userlog nat export source-ip 9.9.9.9
# Enable the NAT log function on Device A.
[DeviceA] nat log enable
You must run XLog on the NAT log server or the system log server to view NAT log
information.
Solution: Enable debugging for NAT. Try to locate the problem based on the
debugging display. Use other commands, if necessary, to further identify the
problem. Pay special attention to the source address after the address translation
and ensure that this address is the address that you intend to change to. If not,
there may be an address pool bug. Also ensure a route is available between the
destination network and the address pool segment. Be aware of the possible
effects that the firewall or the ACLs have to NAT, and also note the route
configurations.
Solution: Check whether the internal server host is properly configured; whether
the router is correctly configured with respect to the internal server parameters,
such as the internal server IP address. It is also possible that the firewall that has
Vlan -int1 Eth1/1
1.1 .1.1/24
Eth1/0
Device A
Eth1/2
NAT log server/system log server
3.3.3.7/24
Troubleshooting NAT
Loop 1
2.2.2.2/24
Eth1/0
1.1.1.4/24
Device B
1827