DNS behavior of a Cisco router are important issues for the CCNA exam and production networks in the real world, and if you can not probable there were so many DNS details before you start studying for the exam! In this tutorial we will contact the name of IP-server command and its proper use.
If a command is incorrect on a Cisco router that is the default behavior of the router to try to resolve the problem through DNS. First, the router for an IP Host table of the local router does not fulfillThis resolution – which is what concerns the "translation" output word. If there is any IP host table or the IP host table contains an entry for entering, the router will send a mission to resolve this name groped through a remote DNS server. To prevent this transfer, enter the global command no ip domain-lookup. Of course, the use of hostnames to resolve DNS Lookup IP domain should be reactivated when it was switchedout.
R2 # Contin
Translating Contin … domain server (255.255.255.255)
% Unknown command or computer name, or be able to find the address of the computer
A command is mistyped as "duration". Default Cisco routers, this item will be at the local level through a Table Host IP, the solution does not exist on the router. A broadcast is then sent to a DNS server to perform name resolution to find. The DNS lookup attempt must time before the configuration cancontinue.
R2 # conf t
R2 (config) # no ip domain-lookup
R2 # Contin
Translating Contin "
% Unknown command or computer name, or be able to find the address of the computer
With "no ip domain-lookup" configured, the router does not try to find a remote DNS server. You see there is no local resolution configured and almost immediately send a message to the console that the name can be resolved.
R2 # conf t
R2 (config) # ip domain-lookup
R2 (config) # ipNameserver 10.1.1.1
R2 # Contin
"Translating Contin … domain server (10.1.1.1)
A DNS server installed on the network with the IP address 10.1.1.1. DNS lookup is enabled with the command ip domain-lookup again, and enter the IP address of the DNS server with the name of IP-server command.
It 'just so easy to say, a Cisco router exactly where the DNS server!
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