SO I'm done with the command
"tar -xzvf <postfix etc"
"cd postfix"
then the next command is the "make -f Makefile.init makefiles"

That comes up with this annoying error! I've spent 12 hours searching for the solution for this error, but can't find any :3
bin'sh makedefs) >makedefs.tmp
https://gyazo.com/66f00f7088023d2719b33cddc0a8d7ba

I've tried different kind of distros. out of 12 distros I have used, only 3 can proceed to postfix, and has the same error.

The three distros have the same error are: "Slackel, Salix and Vector Linux" These are all slackware-based LINUX!

Please do help me with this error. thanks

May I ask why are you building from source and why you are trying to install such an old version?

I actually don't care, this is just a requirement from school, need to install a "DNS,Apache,php,postfix,dovecot and SquirrelMail" just a compliance. And of course for me to be able to learn. "Linux administration"

OK, without digging deep into this my first guess would be postfix-2.6.5 is too old for 3.x.x kernel.

Thank you for your opinion, do you think that is the cause? Because it worked just fine on Slackware itself, but our instructor doesn't want us to use Slackware, because we already know how to, since Slackware is what we always do in our lab activity.

Usually there is a "./configure" step so it can find where different distributions store configuration information.

Depending on the package, the default may exist... but when it doesn't the configure step can create/replace what is missing.

... hm. It seems Postfix doesn't use autoconf. Sorry about the wrong info above.

According to the install documentation (http://www.postfix.org/INSTALL.html), there should be a shell script in the top level of the kit called "makedefs".

You have to modify it for unknown systems - and your link shows the system you are trying to compile it on is "unknown".

Thank you for reply! Uhmmm, I don't know where to modify! :3

There should be some other configurations already present for examples.

Don't forget the possible changes needed in util/sys_defs.h file too.

Sometimes you can identify a different system that works the same as yours, and just copy the data for it. If something doesn't quite work right, you can then make changes to the new entries.