dns.msftncsi.com DNS Requests Every Few Seconds

Over the week­end, I updat­ed my wire­less router to the lat­est revi­sion of ASUSWRT-Mer­lin. I also decid­ed to update my Diet­Pi Pi-hole to their lat­est builds. Due to a full code rewrite of Diet­pi, it meant a com­plete rebuild for that sys­tem. The release of ASUSWRT-Mer­lin also sug­gest­ed reset­ting to fac­to­ry defaults due to some major changes. Every­thing was about to be new again.

Once I got every­thing rebuilt and run­ning, I noticed requests com­ing from my fire­wall to my diet­pi every 10 sec­onds or so for dns.msftncsi.com. I imme­di­ate­ly assumed this was some Microsoft teleme­try noise on my net­work from MS NLA. How­ev­er, the queries were com­ing direct­ly from my fire­wall which seemed odd. Anoth­er search led me to a post on the Pi-hole dis­course. After I ran nvram show | grep dns_probe, it was clear I found the cul­prit.

admin@gw:/tmp/home/root# nvram show | grep dns_probe
dns_probe_host=dns.msftncsi.com
dns_probe_content=131.107.255.255 fd3e:4f5a:5b81::1

I ran the fol­low­ing three lines and con­firmed the traf­fic stopped. No reboot was nec­es­sary. The first post I read rec­om­mend­ed set­ting dns_probe_content to 0.0.0.0 and dns_probe_host to “” (effec­tive­ly blank). I lat­er found a post by RMer­lin that explains set­ting dns_probe_content to blank dis­ables the watch­dog ser­vice but effec­tive­ly dis­ables the dual WAN fea­ture. It would make sense that dual WAN would require a watch­dog ser­vice. So, if you use dual WAN, don’t do this. Oth­er­wise, you should be fine.

admin@gw:/tmp/home/root# nvram set dns_probe_content=
admin@gw:/tmp/home/root# nvram set dns_probe_host=
admin@gw:/tmp/home/root# nvram commit

RPM/yum Database Corruption

Jumped onto my serv­er and noticed a few out of date pack­ages. A quick % sudo yum update report­ed the fol­low­ing:

error: rpmdb: BDB0113 Thread/process 12323/139745043400512 failed: BDB1507 Thread died in Berkeley DB library
error: db5 error(-30973) from dbenv->failchk: BDB0087 DB_RUNRECOVERY: Fatal error, run database recovery
error: cannot open Packages index using db5 - (-30973)
error: cannot open Packages database in /var/lib/rpm
CRITICAL:yum.main:

For­tu­nate­ly, the fix was easy:
% sudo rpm --rebuilddb

Once com­plete, yum update worked like new.

Weekend Reading - April 15, 2016

Blogs / News

Weekend Reading - March 25, 2016

Con­fer­ence / Mee­tups

Blogs / News

Weekend Reading - March 18, 2016

Blogs / News

Weekend Reading - March 11, 2016

Conference / Meetups

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Weekend Reading - March 4, 2016

Conference / Meetups

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Weekend Reading - February 26, 2016

Conferences/Meetups

Blogs/News

Weekend Reading - February 19, 2016

Fedora 21 on a Macbook Air

freedom-infiniti-fedoraAfter going around and around try­ing to get usb boot media work­ing with my Mac­book Air, I final­ly came across a gem that did the trick. I had an EFI par­ti­tioned disk and regard­less of using Unet­bootin, Yumi, and Lili, I was only able to boot just to receive this error:

error: file ‘/isolinux/vmlinuz0’ not found.
error: you need to load the ker­nel first.

The fix was to clean up my usb disk and then use Rawrite32. I found these instruc­tions on the fedo­ra project wiki under Win­dows Quick Start.

First, I had to blow away every par­ti­tion on my usb device. Note: Take care to list disk and select the cor­rect disk before run­ning clean.

C:\> diskpart
DISKPART> list disk
DISKPART> select disk 1
DISKPART> clean
DISKPART> exit

Once com­plet­ed, down­load and install Rawrite32. When you launch Rawrite32, select Open. You’ll have to hit the drop down to show all files so you can select the ISO. Under tar­get, you should see your USB device to write to.  Hit Write to disk… and you should be ready to boot once it does it’s thing.