Networking is a practical subject. The more practice we do, we get better at it. With great enthusiasm, I downloaded Cisco Paket Tracer for the hands-on.
After initial login, during practice typed a wrong command. Guess what I need to wait till the DNS/Domain lookup got timed out. Got in this situation multiple times. Started getting frustrated with the wait during the wrong command and then next command I wanted to tray.
% Unknown command or computer name, or unable to find computer address
Concept Behind the behaviour
Domain server lookup, i.e. “IP domain-lookup” is by default enabled on the routers. DNS is used to translate Name-to-IP for inter-router communication in a large network setup. If a word or phrase typed and Router OS not able to recognise it as a valid command, it takes it as “hostname”. Router OS try to resolve the name on the network. The default time out is a minute.
This default behaviour is not really required when we are practising or when we have a small network that can be managed without the DNS lookup. Routers Os gives us an option to disable the default behaviour.
Enter configuration commands, one per line. End with CNTL/Z.
Router1(config)#no ip domain-lookup
Do not forget to press CNTL/Z to save the changes.