1. Obtain the packet headers from the PCs that fail to or successfully access the weblogic server.
Use the Follow TCP Stream tool to check the packet header from the PC that fails to access the weblogic server. There is the failed HTTP request, and the weblogic server once sent a response to the client. As shown in the following figure, the weblogic server sends HTTP 302. After HTTP 302 is redirected, the PC continues to send a request to the weblogic server. The weblogic server returns HTTP 200, but no text is returned.
2. Check whether the weblogic server works properly.
A user can access the weblogic server from the CP Centre, indicating that the weblogic server works properly. In addition, the aggregation switches is normal.
3. Ping the IP address of the weblogic server from a computer in the FICO.
The TTL is 252 and 253 sometimes, indicating that the path where data packets are transmitted changes. The firewall may block ping response packets as attack packets.
4. Check whether the firewall is normal.
Run the undo firewall session link-state check tcp command on the firewall, and test the PCs. The fault persists. The firewall is normal.
5. Check the L2VPN link of the egress router or ISP.
Check the packets about access failures. The following susceptible data packets are found:
Analyze the data packets. There is the segment loss in TCP packets returned by the weblogic server.
When a PC in the FICO sends large non-fragmented ping packets to the weblogic server, the ping operation fails. For example, the ping 10.248.0.15 –l 1446 –f command is used.
Check packets about successful access. There are many response packets with fragment loss. There is a possibility that a PC successfully accesses the weblogic server.
Fragment packets are lost when being transmitted along the ISP link. That is, the TCP MSS is incorrect.
6. Change the TCP MSS.
Run the tcp adjust-mss 1200 command in the interface view of the AR to change the TCP MSS to 1200.
After the MSS is changed, all PCs in the FICO can successfully access the weblogic server.