Custom Debian-Installer images for DCS

Curses interface Authenticating using the curses interface GTK interface Successful connect with the GTK interface

It can be a little awkward installing Debian in my Department's labs.

After obtaining a DHCP lease, you cannot establish any useful connection without first authenticating against a HTTP Basic page. However, as this page uses SSL and D-I's Wget is not linked against any SSL libraries, you are a little stuck.

To solve this (and to avoid resorting to ugly hacks), I created a udeb that prompts the user for their username and password (see screenshots above) and then authenticates using a statically-linked build of Curl. It seems to be fairly robust, and only bloats the ISO by about 200KB.

I've also preseeded a number of options suitable for DCS, such as using the local mirror and assuming UK locales and keyboard, etc. My modifications are available, along with some documentation on how to recreate my images. I have also uploaded a few images to our mirror.

D-I hacking turns out to be quite fun and relatively painless, but I'm now stuck for a useful project to use it again, and I probably don't know enough yet to tackle some of its Lenny goals either. Any ideas? Oh, if some d-i guru can explain how I can force the display of the "Choose suite" question without patching choose-mirror, that would also be excellent.

Comments (5)


Nice work. Considering the prevalence of captive portals, perhaps a generalized version of this could become a standard part of the installer. You could preseed an URL, POST or GET, and a list of form fields.

Bonus if you autodetect the captive portal with a smoke test of some kind, such as by grabbing a standard page and checking for an HTTP redirect.

Dec. 2, 2007, 10 p.m. #
Colin Watson

You mean mirror/suite? I'm afraid you can't alter the priority of a question by preseeding; about the only thing you could do is change the whole installer to run at priority medium.

(Well, there's the horrible hack option of adding a bit of code that runs before choose-mirror and asks mirror/suite separately, I suppose. But ugh.)

Dec. 3, 2007, 5:56 p.m. #

Changing the installer to run at medium isn't optimal as it means the main menu always appears and bloats the preseed considerably. Recreating the mirror/suite question is an option of course, and probably preferable to patching 'choose-mirror' (no need to keep changes in-sync, etc.)

Dec. 3, 2007, 7:07 p.m. #
Eddy Petri?or

does feeding mirror/suite from the command line fits your needs?

Dec. 3, 2007, 11:58 p.m. #

@Eddy: Not really - I want it to always be asked: I'm not aiming for an completely unattended install, just wanted to automate tedius questions.

Dec. 4, 2007, 12:20 a.m. #