UNIX for Dummies Questions & Answers

hi friends!
i know that host names are put into a file called
/etc/hosts
which can have three fields as
<ip address> <fully qualified DNS name> <alias>
eg.
255.255.17.1 abc.xx.yy abc

so to telnet to the machine whose ip is as above
(255.255.17.1),i can do telnet abc instead which is short and sweet,
so if now i remove the alias part of the above ip,i shouldnt be able to telnet
to this machine in the same manner,but it's not working,
after removing the alias here,still my machine can telnet to abc.xx.yy as
telnet abc

there are couple of reasons may be...

1. you have to refresh nscd daemon:
service nscd restart

see man nscd for more...

2. you may have the same entry on dns server so if the file nsswitch.conf contains entries for both: files dns, then try: host or dig the address

3. your computer is a part of NIS and it propagates a list. see ypcat command to discover the maps it may have.

as there's much of everything, get "UNIX Essentials and UNIX Core" DVD course as it addresses many issues of this sort.

hi
i had access to one hp machine and
to deactivate telnet i got the information from this forum,
according to which one needs to comment out
one line
"telnet -------------" in a file called /etc/inetd.conf
then use kill -1 <pid_of_inet_process>

kool its working on hp machine,so how to make it work on linux machine.
i tried with modifying the file "/etc/hosts" but its not working.

these two have nothing in common. the initial question was about DNS resolution and inetd.conf is a completely different, it launches services by requests on specific port. If you need to deactivate telnetd you comment in inetd.conf but it has nothing to do with a way it is resolved from a network.