Part of finding out for CCNA exam success is preserving all these new instructions straight in your head! And let's face it, there are plenty of commands you should know in an effort to move the CCNA exam and earn that certification. Here's an evaluation of some essential distance vector and static routing instructions you must know, together with their correct utilization and console output.
Bandwidth
IGRP makes a default assumption that any Serial interface running IGRP is connected to a T1 line, which runs at 1544 KBPS. With equal-value load-balancing enabled by default, this can be an undesirable assumption.
To change IGRP's assumption, use the bandwidth command on the serial interface in question. Note that this command does NOT actually affect the bandwidth obtainable to the interface; it merely changes IGRP's assumption of the bandwidth.
R2conf t
R2(config)int s0
R2(config-if)bandwidth 512
Clear ip route *
This command clears your routing table of all non-static and non-linked routes. In a lab environment, it's very handy as a result of it forces your routers operating routing protocols to ship and request updates, fairly than ready for the recurrently scheduled updates.
R2clear ip route *
Debug ip igrp events
Debug ip igrp events permits you to see IGRP updates being despatched and requested. Here, the debug is run and then the routing desk is cleared. The router instantly broadcasts replace requests by way of the IGRP-enabled interfaces.
R2debug ip igrp occasion
IGRP event debugging is on
R2clear ip route *
06:02:51: IGRP: broadcasting request on BRI0
06:02:fifty one: IGRP: broadcasting request on Serial0.123
Debug ip igrp transactions
To configure IGRP unequal-value load-sharing with the variance command, you've obtained to know the metric of the much less-desirable routes. EIGRP retains these in its topology desk; IGRP has no such table.
To get the metrics of routes not within the routing table, run debug ip igrp transactions. To drive IGRP updates, the routing table below was cleared with clear ip route *.
R2debug ip igrp transactions
IGRP protocol debugging is on
R2clear ip route *
06:05:33: IGRP: obtained update from 172.12.123.1 on Serial0.123
06:05:34: community 1.0.0.zero, metric 158750 (neighbor 501)
Debug ip rip
R2debug ip rip
IP protocol debugging is on
R2clear ip route *
6:14:53: RIP: acquired v2 replace from 172.23.23.3 on Ethernet0
6:14:fifty three: 1.0.0.0/eight by way of 0.0.0.0 in 16 hops (inaccessible)
6:14:fifty three: 1.1.1.1/32 via 0.0.0.0 in 2 hops
6:14:53: 172.12.0.0/sixteen through 0.0.0.zero in sixteen hops (inaccessible)
6:14:fifty three: 172.12.12.2/32 by way of 0.0.0.zero in 2 hops
6:14:fifty three: 172.12.13.0/30 by way of 0.0.0.zero in 1 hops
6:14:fifty three: 172.12.123.zero/24 through 0.0.0.zero in 1 hops
6:14:53: 172.23.0.zero/16 via 0.0.0.zero in sixteen hops (inaccessible)
Run debug ip rip to troubleshoot routing update issues, RIP authentication issues, and to view the routing update contents. Clear ip route * was run to clear the routing table and to drive a RIP update.
To configure a static path to a given destination IP tackle, use the ip route command. The vacation spot is followed by a subnet mask, and that may be followed by both the subsequent-hop IP handle or the exit interface on the local router.
To configure a default static route, use both of these commands.
You can have any number for the primary "0.0.0.0", since the second set of zeroes is the subnet mask. This means that any destination will match this route statement.
That is a superb evaluate to get started with! I will be back tomorrow with Part II of this CCNA examination command evaluation!
DNS behaviors of a Cisco router are important matters for each the CCNA examination and real-world manufacturing networks, and also you probably didn't know there have been so many DNS particulars before you started finding out for the examination! In this tutorial, we'll have a look at the ip identify-server command and its proper usage.
When a command is mistyped on a Cisco router, the default behavior of the router is to try to resolve it via DNS. First, the router looks for an IP Host desk on the local router to perform this resolution - that's what the "translating" word within the output is referring to. If there's no IP Host desk or the IP Host table doesn't include an entry for what you typed, the router will ship a broadcast in an attempt to resolve this identify via a distant DNS server. To prevent this broadcast, enter the global command no ip domain-lookup. After all, to make use of DNS to resolve hostnames, ip domain-lookup would have to be reenabled if it's been turned off.
R2contin
Translating "contin"...area server (255.255.255.255)
% Unknown command or computer identify, or unable to seek out pc deal with
A command is mistyped as "contin". The Cisco router's default behavior is to resolve this entry locally by way of an IP Host desk, which is not present on the router. A broadcast is then despatched out to find a DNS server to carry out the name resolution. The DNS lookup attempt should day out earlier than the configuration can continue.
R2conf t
R2(config)no ip domain-lookup
R2contin
Translating "contin"
% Unknown command or computer name, or unable to find pc address
With "no ip area-lookup" configured, the router doesn't attempt to discover a remote DNS server. It sees there is no such thing as a local resolution configured and almost immediately sends a message to the console that the identify can't be resolved.
R2conf t
R2(config)ip domain-lookup
R2(config)ip title-server 10.1.1.1
R2contin
Translating "contin"...domain server (10.1.1.1)
A DNS server is installed on the network with the IP handle 10.1.1.1. DNS lookup is reenabled with the command ip domain-lookup, and the IP address of the DNS server is specified with the ip identify-server command.
It is just that straightforward to tell a Cisco router precisely where
