*nix Tip of the Day: Dynamic DNS
It's nice to have DNS records for all of your computers. It's a
giant pain in the ass to remember IP addresses, especially if you're on
something like a cable connection, where the IP address is dynamic (but
only changes every month or two). Now, you could go ahead and use
DynDNS or No-IP or something. But those are lame. You have to
use a subdomain of one of their domains, and you have to use their
software to update. You might be wondering if there's a better way.
Well, there is. Standard DNS supports updating, it turns out. In BIND,
this is managed through the allow-update parameter. I had some free
time this week after I finished finals, so I went ahead and set it up,
along with the other trimmings required for Wide-Area Bonjour. It's
cool, so I thought I'd post a bit.
The most important resource for all of this stuff is dns-sd.org.
Aside from a couple of minor errors that I corrected and an update for
OS X 10.5+, this Tip will be based off of the guides from that site. So
credit to them.
*nix Tip of the Day: VMS
Okay, so this is maybe a little unusual, but today's "*nix Tip of the
Day" isn't about Unix/Linux/etc. at all. Instead, it is about their
antiquated archenemy: VMS. First, a little bit of history:
Way back in 1970, the PDP-11 was hot stuff. Ken Thompson, Dennis
Richie, Brian Kernighan, and others at Bell Labs were writing what would
become Unix for the PDP-11 (well, for the PDP-7 at first, but nobody
talks about that). Unix was a huge improvement over what DEC shipped
with the PDP-11, DOS-11 and RT-11. This couldn't stand, so Dave Cutler
at DEC designed VMS. It was a new operating system, with lots of fancy
features, like networking and, uh, lots of upper-case letters.
VMS and Unix sort of battled on. Or so some people would have you think.
Really, Unix won early on and VMS stumbled along with corporate
financing and an obnoxiously difficult-to-use interface. It passed from
DEC to Compaq to HP, from the PDP-11 to the Alpha to the Itanium. And it
still lives on, churning away in scary back-rooms here and there.
So, why do I bring this up? Well, as some of you may know, Harvey Mudd
College has a few VMS machines around. The most well-known of these (to
students) is thuban, which is a 667MHz DEC Alpha running OpenVMS
7.3-2. Today, I had the, uh, interesting experience of using it, and
thought I'd share my impressions with my readers. You can see the proof
of my VMS skills at my VMS homepage. That's right, I'm on the
Internet. And on DECnet.
Just in case anybody cares, I've upgraded the site to the latest and
greatest (WordPress version 2.8.1). No user action is required at this
Also, the code behind the blog is now valid HTML5, and there's a Google
Friend Connect widget so you can participate in discussions without
creating yet another account (woo!).
New GPG Key
As you may have seen around the Internet, there was a
fairly significant break in the SHA-1 hash function, which is used
by default in GnuPG. This is worrisome, since GPG/PGP signatures are
one of the only things I'd actually trust to verify somebody's identity
online. So I've generated a new key with a 2048-bit RSA primary (for
SHA256 and SHA512 support) and a 4096-bit ElGamal encrypting key (which
took about 15 minutes to generate, so better be worth it). The key ID is
CB8AA0FF, and the fingerprint is
5C35 D713 3E10 9A19 FFFC F58A 68E8 3B57 CB8A A0FF …
So, I'm currently in San Clemente for a couple of days before going back
to Claremont. As usual, the trip cross-country was fun. Lots of hours
in a tin can. Anyhow, something amusing happened at T.F. Green when
I was leaving. TSA got confused by my backpack in the X-Ray machine
(understandable, since it's got a zillion wires and such in it). So they
start going through it and they find that I brought a copy of Mohsin
Hamid's The Reluctant Fundamentalist. The guy then ignores the rest
of my bag, pulls out the book, and runs it through …
*nix Tip of the Day: sudo
I've mentioned sudo in these tips before. It's a neat little utility for
executing commands as somebody else. Well, today I bring you a handy
guide I found on using sudo. I already knew most of the stuff, but some
of it was new, and it looks pretty good as a starter for new users. So
enjoy this article on sudo basics by A.P. Lawrence.