UNIX for Dummies Questions & Answers

Hi all,

I am doing an assignment and there is something I am confused about.
The requirement is to set up the DNS and sendmail to two domains: lab1 and lab2, with hosts of mail.lab1 and mail.lab2 both acting as DNS server and email server, and send mail from root@lab1 to root@lab2. However, it always complains about host unknown about lab2. I tried dig mx lab2, and it could get the correct address of the mail server. But when I send the mail and use tshark to monitor the pakcets, I see the mail server is always querying lab2.localfarm to get the mx record. I am guessing it is because the name of lab2 is not FQDN. I have already deleted the line of "search localfarm", and tried "search ." but still no luck.

More interesting information is, if I send to root@mail.lab2, it works (but it is not the requirement). And if I changed the domain names to lab1(2).net, both @mail.lab2.net and @lab2.net are working. Can anyone help me out? I have bee struggling with this problem for over two weeks.

Thanks for your help!

Homework?
Please look at:
https://www.unix.com/homework-coursew...ons-forum.html

Might be worth checking the contents of the sendmail configuration file which decides where to look up names:

/etc/mail/service.switch

Sorry I didn't know that. I'll try to seek help somewhere else, because I really couldn't figure it out.
And methyl, I checked the nsswitch.conf before, changed it into "check dns first", but no luck. I guess it is really rare because nobody at work would have to handle this situation.

These are two different files and they both need to be correct:

Code:

/etc/nsswitch.conf
/etc/mail/service.switch