RESOLVED - Issue with DNS Resolution

[F M Waterman]

Howdy folks,

I have a real head-scratcher of an issue with one of the two computers running Mint 18.2, Cinnamon desktop that are hard wired to my modem/router.

Basically, the one computer acts as though it doesn't have a connection to the Internet. My VPN times out after launch, I can't update packages through the update manager or the command line and Chromium and Firefox both return errors stating they were unable to resolve the URL of my homepage.

On the other hand, I AM able to PING IP addresses to my heart's content, so a connection IS present, there's just something bollocks'd up within Mint and I'll be darned if I can suss out what is wrong! It's frustrating to say the very least.

One of the first things I thought to try was disabling ALL of the extensions/add-ons for the browsers. That had no effect at all.

One thing that may be related is earlier in the day, before the issue with Internet connectivity was discovered, I was attempting to change the login procedure for the affected computer from automatically logging me on to requiring me to enter my password in order to logon. This was being done in an attempt to stop the gnome-keyring-daemon from popping up off and on during a session and then not shutting down properly when I would shut the computer down, forcing me to kill the process. Quite honestly, the loss of connectivity got me so distracted that I never bothered to determine if adjusting the setting in the password tool solved the keyring issue or not, although when I tuned the computer off for the night, I DID only see one advisory that the daemon was still running instead of the usual three I had been seeing. Don't know that it has any bearing on the connectivity issue, but in the interest of complete disclosure, etc...

I am hopeful that someone with more Linux and networking experience than I will read my tale of woe and will tumble to just what I have done to this poor, defenseless computer!

[catweazel]

Code: Select all

inxi -Fxz

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[F M Waterman]

The information that you requested:

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 ~ $ inxi -Fxz
System:    Host: HTPC-GX620 Kernel: 4.10.0-33-generic x86_64 (64 bit gcc: 5.4.0)
           Desktop: Cinnamon 3.4.6 (Gtk 3.18.9-1ubuntu3.3)
           Distro: Linux Mint 18.2 Sonya
Machine:   System: Dell product: OptiPlex GX620
           Mobo: Dell model: 0MD525 Bios: Dell v: A11 date: 11/30/2006
CPU:       Dual core Intel Pentium D (-MCP-) cache: 1024 KB
           flags: (lm nx sse sse2 sse3) bmips: 11970
           clock speeds: max: 2992 MHz 1: 2992 MHz 2: 2992 MHz
Graphics:  Card: Advanced Micro Devices [AMD/ATI] Turks PRO [Radeon HD 7570]
           bus-ID: 01:00.0
           Display Server: X.Org 1.18.4 drivers: ati,radeon (unloaded: fbdev,vesa)
           Resolution: 1280x720@60.00hz
           GLX Renderer: Gallium 0.4 on AMD TURKS (DRM 2.49.0 / 4.10.0-33-generic, LLVM 4.0.0)
           GLX Version: 3.0 Mesa 17.0.7 Direct Rendering: Yes
Audio:     Card-1 Intel 82801G (ICH7 Family) AC'97 Audio Controller
           driver: snd_intel8x0 ports: ec00 e8c0 bus-ID: 00:1e.2
           Card-2 Advanced Micro Devices [AMD/ATI] Turks/Whistler HDMI Audio [Radeon HD 6000 Series]
           driver: snd_hda_intel bus-ID: 01:00.1
           Sound: Advanced Linux Sound Architecture v: k4.10.0-33-generic
Network:   Card: Broadcom NetXtreme BCM5751 Gigabit Ethernet PCI Express
           driver: tg3 v: 3.137 bus-ID: 02:00.0
           IF: enp2s0 state: up speed: 1000 Mbps duplex: full mac: <filter>
Drives:    HDD Total Size: 640.1GB (2.4% used)
           ID-1: /dev/sda model: WDC_WD6400AAVS size: 640.1GB
Partition: ID-1: / size: 4.7G used: 740M (17%) fs: ext2 dev: /dev/sda3
           ID-2: /usr size: 19G used: 5.6G (32%) fs: ext4 dev: /dev/sda7
           ID-3: /boot size: 453M used: 122M (29%) fs: ext4 dev: /dev/sda1
           ID-4: /tmp size: 9.4G used: 22M (1%) fs: ext2 dev: /dev/sda11
           ID-5: /home size: 19G used: 733M (5%) fs: ext4 dev: /dev/sda6
           ID-6: /var size: 19G used: 1.4G (8%) fs: ext4 dev: /dev/sda10
           ID-7: swap-1 size: 6.14GB used: 0.00GB (0%) fs: swap dev: /dev/sda5
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: No active sensors found. Have you configured your sensors yet? mobo: N/A gpu: 36.5
Info:      Processes: 203 Uptime: 2 min Memory: 562.2/3508.7MB
           Init: systemd runlevel: 5 Gcc sys: 5.4.0
           Client: Shell (bash 4.3.481) inxi: 2.2.35 
 ~ $ 

I am interested to learn: What information pertaining to the issue I have described do you hope to obtain from this output?

[F M Waterman]

I spent quite a bit of time thinking about this issue last night.

Clearly, it boils down to the effected computer's ability to resolve DNS addresses. Therefore it MUST involve some part(s) of Mint that are involved with that process.

Falling back to look for similar issues with Ubuntu 16.04, I found a single report made by a user that described an issue almost identical to the one I am having with this computer. Thankfully, this user was experienced and provided an excellent step-by-step of the diagnostic process he went though. Much to my dismay, there had only been a single response to his pleas for help and that response turned out to be a dead end.

And then IT HIT ME. I had forgotten, but I had installed a program provided by my VPN service! The software is less than a year old and was designed primarily on and for Ubuntu 16.04, so I took a shot. Now I'm left wondering if in installing that program it didn't alter some system's files?

This afternoon, I began uninstalling it though Mint's software manager. The process began right enough until it reached 75% complete and that is where I left it in order to come in here and write this followup post. I just now checked on its progress and it was still at 75%, so I shut it down and launched Synaptic (which I probably should have done to begin with). Synaptic finished the removal and reported nothing broken, so I tried Chrome and ran into the same damn problem!

CRAP! CRAP! CRAP! I just know that GD program corrupted some files. And although I really don't want to, I'm just going to reinstall Mint all over again. CARAMBA! QUE COSA! (Sorry, that's the best I can do for swearing in a foreign language in a 'G' rated forum)!

Well, guess I'm gonna close this issue down and call it resolved even though I didn't find the magic wand fix I had hoped for!

[greerd]

Did you look in /etc/resolv.conf?

[F M Waterman]

Yes, I did look at the file /resolv.conf, but as I had no idea as to what information it should contain, the conclusion I reached was that the path of least resistance lay in beginning over again from a fresh install. As I hadn't put in much time and effort into customization of the install of Mint and had under 300 MB of files to back up, it seemed like the best thing to do.

And since I am now able to communicate with you and the rest of the forum from that very same computer, I would have to conclude I was correct.

Which only goes to show than even a blind squirrel will find an acorn now and again!