Yak shaving as a troubleshooting methodology

BoneKracker · Veteran Joined: 14 Mar 2006 Posts: 1498 Location: U.S.A.

So the most recent udev upgrade (197-r4) brings with it a .rules file to block it from ass-raping your network interface names into unintelligible gibberish such as "enp1s7", for now (i.e., apparently said ass-raping is the ultimate plan). I'm like, "no big deal" on your basic PC, but on my router/firewall, I've got so much shit on there that has interface names in various places (firewall rules, blacklisting scripts, dhcp configs, resolver configs, samba configs, etc., etc.), that I start thinking about how this kind of sucks.

In the process of looking into this and exploring the significance of the change (the upshot of which is that it does make sense and you can still do what you were doing before if you want to), I discover that the headless box I've been using as a firewall/router for years is using udhcp to get its addresses from the isp's dhcp server, and it's not using dhclient, which is what I've got installed. (See I cleverly avoided having a "modules" entry in my /etc/conf.d/net file, by only having one dhcp client installed.)

Wait. Wtf? How can it be using udhcp when I don't even have it installed?

I look at my configuration for dhclient, and recall that I have two "append nameserver" entries there to manually add freedns and google dns servers to the pair that comes from my ISP's dhcp server. I can quickly confirm whether if dhclient being used by looking for these in my resolv.conf file. Shit. Not there. Nor are they in the extra resolv.conf file created by OpenResolv for dnsmasq (so that the local dns server I operate for my network and to cache upstream responses will be dynamically updated according to what my ISP says I should be using).

Hey, wait a minute. Could this be related to why I've been getting dns related errors lately when trying to connect to gentoo.org addresses (and only gentoo.org addresses). Well, first I'll fix this.

Reboot and watch the startup of the normally headless box. Uh... apparently, I do have it installed, because there it is, saying, "Starting udhcp....". Oh, that's right; it's part of busybox, and I have busybox installed. But why wasn't this happening before then, because I've always had busybox installed? Oh, I know, somebody must have changed the default configuration for busybox (which I've never modified and just keeps getting replaced in /etc/portage/savedconfig every time it updates) such that my busybox instance now includes udhcp. How nice. Or maybe they chanced the order of preference of alternative dhcp clients within OpenRC.

Anyway, I'll just add that "modules_eth0=dhclient" entry to the conf.d/net file... yup, that fixed it. Now I've got all four dns servers as upstream for my own.

So, now, what about the "unable to obtain address for foo.gentoo.org" problem? I do an 'nslookup google.com <isp nameserver's ip address>', and ..blink, right answers.
So I do 'nslookup gentoo.org <isp nameserver's ip address>, and ....... jack squat
nslookup gentoo.org 4.2.2.1 ...blink, right answer (that's freedns)
nslookup gentoo.org 8.8.8.8 .....blink, right answer (thats google dns).

So apparently, my ISP's dns servers sometimes do not have a record for gentoo.org, for some reason. This was an intermittent problem only, since my local dns server is a caching nameserver. So when it was able to get an address, it kept it for a while. However, since I only noticed myself having connection problems over the last couple of days, then one of two things is true:

a) the busybox config (stable x86) changed in the last few days, causing my router to use a default udhcpc dhcp setup, which caused my two "append nameserver" entries in dhclient.conf to be ignored, introducing this hiccup; or

b) whatever is causing gentoo.org's entry to not always be present in my ISP's nameservers started to happen just recently, and I've unknowingly been booting my (headless) router using an unconfigured udhcp client for a long time. :lol:

Anway, set out to solve one problem, end up fixing a different one. :lol:

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Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four.

pjp · Posted: Sat Jan 26, 2013 5:15 pm Post subject:

Wow. Not a freakin' thing about yaks.

BTW, congratulations on the (Blue Belt). :P
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In Loving Memory
1787 - 2008

wildhorse · Posted: Sun Jan 27, 2013 12:20 am Post subject:

Never tried yaks before, but pussy shaving works for me.

Prenj · n00b Joined: 20 Nov 2011 Posts: 7 Location: Mostar, BiH

BoneKracker · Veteran Joined: 14 Mar 2006 Posts: 1498 Location: U.S.A.

_________________
Oldthinkers unbellyfeel INGSOC.
-- Headline of a document on Winston Smith's terminal in his cubicle at the Ministry of Truth, seen briefly in the background in one scene of the movie rendition of Nineteen Eighty-Four.

sikpuppy · Posted: Sun Jan 27, 2013 1:35 am Post subject:

Shaved pussy.

BoneKracker · Veteran Joined: 14 Mar 2006 Posts: 1498 Location: U.S.A.

Prenj · n00b Joined: 20 Nov 2011 Posts: 7 Location: Mostar, BiH