PCs on the Intranet Were Unable to Access the Internal Server Because Intrazone

Ravger · Created Apr 8, 2016 07:08:08

Handling Process

1. The following bidirectional NAT was displayed after global port mapping was configured.

tcp VPN: public -> public
Zone: trust -> trust TTL: 00:00:10 Left: timeout
Interface: G0/0/0 Nexthop: 10.172.11.249 MAC: 00-00-5e-00-01-17
<-- packets:12 bytes:2297 --> packets:18 bytes:3680
10.172.10.99:46915[10.228.187.128:46915]-->10.228.187.128:18888[10.172.10.99:18888]

2. In addition to ports 18888 and 18443, the PC might also access other ports. However, the packets on the PC indicated that the PC did not access other ports of the server.

3. If the PC did not access other ports, the fault might occur because the server accessed other addresses, and a packet analysis proved so. The server accessed its global address instead of the real destination. To resolve this issue, interzone NAT or global NAT server must be configured.

When the communication between the PC and server was successful, the server (10.172.10.99) initiated access to 10.228.187.128. In this case, the traffic in both directions matched the same NAT server. This scenario is also known as bidirectional NAT. In the case of unsuccessful communication, the source port of the initiator was not 18888. Therefore, the traffic matched NAT in one direction. In this case, the source address of the traffic sent to the server was still 10.172.10.99. However, the request of the PC destined to 10.228.187.128.

Root Cause

The PC accessed the public address mapped to the server through NAT server. However, NAT server was not implemented for the ports. Therefore, intrazone NAT must be configured to resolve the problem.

Solution

Configure intrazone NAT to resolve the problem.

PCs on the Intranet Were Unable to Access the Internal Server Because Intrazone

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PCs on the Intranet Were Unable to Access the Internal Server Because Intrazone

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