单项选择题
A.IP Helper is used to direct BOOTP clients to a BOOTP server
B.IP Helper is used to prevent the router form forwarding IP broadcasts
C.IP Helper is used to allow IPX clients to communicate with IP-based servers
D.IP Helper is used to accommodate compatibility routers using different IP routing protocols
E.None of the other alternatives apply
单项选择题 RIP and OSPF are configured on the routers as shown in the exhibit. R2 is configured with a two-way redistribution between RIP and OSPF domains. All routers can ping each other， but R1cannot see any of the OSPF routes in its routing table. What could the problem be？（）
单项选择题 Refer to the network shown below： R1 and R2 belong to the RIP routing domain that includes the networks 10.20.0.0/16 and 10.21.0.0/16. R3 and R4 are performing two-way route redistribution between OSPF and RIP. Anetwork administrator has discovered that R2 is receiving OSPF routes for the networks 10.20.0.0/16 and 10.21.0.0/16 and a routing loop has occurred. Which action will correct thisproblem？（）
单项选择题 Refer to the exhibit. The routing protocols EIGRP and OSPF have been configured as indicated inthe exhibit. Given the partial configuration of router R2， which network will be present in the routingtable of R4？（）