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Chapter 10The term Forwarding Information Base (FIB) points to the kernel's routingtable, while the term Routing Information Base (RIB) actually meansrouting daemon's internal routing table.The most used feature of bgpctl is the show command that displays informationabout the current status of peers as shown here:# bgpctl showNeighbor AS MsgRcvd MsgSent OutQ Up/Down State/PrefixRcvdISP B 65003 38700 141 0 01:09:02 182394ISP A 65002 38620 137 0 01:08:41 182322You can also manipulate sessions with peering routers using the bgpctl neighborcommand. For example, you may use the following syntax to temporarily disablepeering with a specific peer:# bgpctl neighbor 10.0.0.2 downTo enable the same peer, you can use the same command, this time with theup command:# bgpctl neighbor 10.0.0.2 upThere may be certain times when you want to clear a session (force a reset on theconnection). This is achievable by using the neighbor clear file:# bgpctl neighbor 10.0.0.2 clearYou can also dynamically add a network prefix to your advertised networks on thefly, using bgpctl:# bgpctl network add 10.10.32.0/20And to remove the network, you can use the network delete command.BridgingUsing the ifconfig(8) utility, which we've discussed in Chapter 7, and the multiplenetwork interfaces installed on your host, you can create a network bridge.Network bridges are used to separate different segments of a network in layer2 ofthe OSI model (for example Ethernet). Unlike routers, a bridge makes forwardingdecisions based on the layer2 (MAC) addresses. In fact, a typical bridge does notunderstand higher levels of the OSI model. A good example of a network bridge is,layer2 network switches. You can consider your bridge a layer2 switch if it hadfewer ports.[ 169 ]