Wrong static router configuration result in the routing loop

Publication Date:  2012-09-13 Views:  136 Downloads:  0
Issue Description
Configure the router static in the network. Router A is the gateway of the network segment 172.16.0.0/24 as default. Router C is the gateway of the network segment 192.168.0.0/24 as default. Router A and Router B connect each other by the segment 10.0.0.0/30. Router B and Router C connect each other by the segment 10.0.0.4/30. All of the conjoint interface of Router A and Router B, Router B and Router C run the OSPF protocol, and import the direct router and static router. PC2 (192.168.0.2) can’t ping the PC3(172.16.0.2), and PC2 connect with Router C, PC3 is in the network segment 172.16.0.0
Alarm Information
none
Handling Process
1 Check the gateway of PC, all right, get rid of this cause

2 Check the OSPF, all right, get rid of this cause

3 Check the routing table of Router A and Router C, found out that they learned the routing information of the other side

4 executer the tracert 192.168.0.2 in router C; found out that message is transferred iteratively between Router B and Router C; doubt that it exist the ring between Router B and Router C. Router C has the configuration as ip route 172.16.0.0 255.255.255.128 10.0.0.5. Router C has the router information to the network segment 172.16.0.0/24、172.16.0.0/25, the next hop are  Router A and Router B. Thus, according to the longest path matching, message to the 172.16.0.0/24 will be transferred iteratively between Router B and Router C until the TTL=0;

Delete the router static of Router C, problem solved.

Ping PC2 from PC1, If it works, problem solved.
Root Cause
1 Configuration of gateway has fault
2 Configuration of OSPF has fault
3 Routing table has fault.
Suggestions
none

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