Re: [vox-tech] postfix and apache
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Re: [vox-tech] postfix and apache
Quoting Charles McLaughlin (email@example.com):
> Cylar Z wrote:
> >I downloaded, compiled, and installed PostFix
> >sucessfully. It seems to be able to send and receive
> >mail via the "mail" command at the prompt.
> I'm no expert on mailservers, but I have to wonder - doesn't your distro
> have a postfix package? Why not use rpm or apt-get?
Second the motion, strongly. I recently appended a comment about these
matters to a _Linux Gazette_ article I was editing for the upcoming
September 2005 issue. (The author, like Matt, had sought out and
compiled a source tarball from the upstream author, in circumstances
where it's not obvious that he should need to.)
 Rick Moen comments: While it's useful and worthwhile to know
about a program's "upstream" development site, where (among other
things) the author's latest source code can be downloaded, there are a
few disadvantages that should be noted, (and some alternative locations
that should be usually be preferred, instead, if such are findable):
1. Absent extraordinary measures on your part, your Linux distribution's
package-tracking system won't know about the program's presence on your
system. Therefore, it won't know to avoid installing conflicting
programs, removing libraries it depends on, etc.
2. You won't get any tweaks and enhancements that may be normal (or
necessary!) for applications on your Linux distribution — unless
you yourself implement them. You won't get security patches, either,
except those written by the upstream author.
3. Along those same lines, the desirable version to compile and run may
well not be the author's latest release: Sometimes, authors are trying
out new concepts, and improvements & old bugs fixed are outweighed by
misfeatures & new bugs introduced.
4. As a person downloading the upstream author's source code directly,
you have to personally assume the burden of verifying that the tarball
really is the author's work, and not that of (e.g.) a network intruder
who cracked the download ftp site substituted a trojaned version.
Although this concern applies mostly to software designed to run with
elevated privilege, it's not a strictly academic risk: Linux-relevant
codebases that have been (briefly) trojaned in this fashion, in recent
years, on the upstream author's download sites, include Wietse Venema's
TCP Wrappers (tcpd/libwrap), the util-linux package, sendmail, OpenSSH,
and the Linux kernel (CVS gateway's archive, only). Unless you are
prepared to meaningfully verify the author's cryptographic signature
-- if any -- on that tarball, you risk sabotaging your system's security.
All of the above are problems normally addressed (and the burden of
solving them, shouldered) by Linux distributions' package maintainers,
so that you won't have to. It's to your advantage to take advantage of
that effort, if feasible. The memory of when a thousand Linux sysadmins,
circa 1993, would need to do all of that work 999-times redundantly, is
still fresh to us old-timers: We call those the Bad Old Days, given
that _today_ one expert package maintainer can instead do that task
_for_ a thousand sysadmins. And yes, sometimes there's nothing
like such a package available, and you have no reasonable alternative
but to grab upstream source tarballs -- but the disadvantages
justify some pains to search for suitable packages, instead.
Depending on your distribution, you may find that there are update
packages available directly from the distribution's package updating
utilities, or from ancillary, semi-official package archives (e.g.,
the Fedora Extras and "dag" repositories for Fedora/RH and similar
distributions), or, failing that, third-party packages maintained by
reputable outside parties, e.g., some of the Debian-and-compatible
repositories registered at the apt-get.org and backports.org sites.
Although those are certainly not unfailingly better than tarballs,
I would say they're generally so.
The smaller, less popular, and less dependency-ridden a package is, the
more you might be tempted to use an upstream source tarball. For
example, I use locally compiled versions of the Leafnode pre-2.0
betas to run my server's local NNTP newsgroups, because release-version
packages simply lack that functionality altogether. On the other hand,
that package's one dependency, the Perl PCRE library, I satisfy from my
distribution's official packages, for all the reasons stated above.
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