DNS error... ethernet connected, no internet :-(

[Externet]

Greetings.

The flag bearer of computer idiots again.

Get the DNS probe error in a Chromebook.  Before was also in the Linux machine. Power cycling all several times allowed me to enter the internet to post this.

There is nothing Windows in my home.  There is nothing wireless in my home.  Have three ethernet wired devices to the gateway (modem?):  A Linux computer; a Chromebook computer, a tuner that receives internet television from the whole planet.  Most of the time all works well, but something gets the 'period' and I cannot solve what cannot understand.  Reading related articles on the web; they assume everyone uses Windows+Chrome+Wifi and do not apply for me to attempt the fix.

Any idiot-proof guidance to cure the misbehavior will be appreciated.

[Ghideon]

23 minutes ago, Externet said:

Any idiot-proof guidance to cure the misbehavior will be appreciated.

Not sure this will help but let's try.
Questions: 
-All internet connected equipment at your home gets the problem, all gets the problem at the same time?
-How is the router (modem) connected to internet? 
-What happens if you power-cycle the gateway when problem occurs, does that fix the issue?

 

(I have had similar looking problems (Linux, Apple and other equipment) and in my case it was the router + DNS service at the ISP that was the issue. Not yet sure if this applies to your case)

[Sensei]

2 hours ago, Externet said:

Greetings.

The flag bearer of computer idiots again.

Get the DNS probe error in a Chromebook.  Before was also in the Linux machine. Power cycling all several times allowed me to enter the internet to post this.

There is nothing Windows in my home.  There is nothing wireless in my home.  Have three ethernet wired devices to the gateway (modem?):  A Linux computer; a Chromebook computer, a tuner that receives internet television from the whole planet.  Most of the time all works well, but something gets the 'period' and I cannot solve what cannot understand.  Reading related articles on the web; they assume everyone uses Windows+Chrome+Wifi and do not apply for me to attempt the fix.

Any idiot-proof guidance to cure the misbehavior will be appreciated.

The first thing any "idiot" should do when there is no internet connection is to use the "ping" command.

A Windows user would do:

Click on Start menu, enter "cmd" to open console.

Then enter "ping". It is the most widely used command for network analysis.

What to ping?

e.g. gateway IP, DNS IP address, host given by name, host given by IP address, device IP etc. etc.

So first you need to know what is your gateway IP address. Do you know your IP address?

If not, before ping, use "ipconfig /all"

https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/ipconfig

which will show you all your interfaces, e.g. WiFi (even if not used / disabled), Ethernet, Bluetooth etc.

Run "cmd", then "ipconfig /all >data.txt" and attach in the reply, so we can see it.

You should have rows with "Default Gateway" which will have address that you should enter to "ping" command as argument.

e.g. "ping 192.168.0.1", use "-t" to have continuous flow of data.

There will be also DNS servers mentioned in output.

You can ping Google DNS. Do you know Google DNS addresses?

8.8.8.8 and 8.8.4.4

How somebody can know what are Google DNS addresses?

Because will use Google to find out:

https://www.google.com/search?q=google+dns+address

(you can do the same with other companies which provide DNS servers, just change name of company in the above query..)

Any network admin will tell you "if your own DNS don't work, use Google DNS". So better remember their IPs in advance..

ping 8.8.8.8

ping 8.8.4.4

What can we see? That they are slooow.

Do you know how to set DNS address to different one?

If you connect through network which has configured DHCP, DNS address(es) will be given by DHCP server.

However if there is something wrong with DNS servers, Internet will stop working in web browsers, but will work through IP given manually.

e.g. ping google.com will fail,

but ping 172.217.22.14 (or whatever google.com resolves to) will work.

 

Linux obviously has equivalent commands for "ping" and "ipconfig":

https://www.google.com/search?q=ipconfig+on+linux

which is "ifconfig"

https://man7.org/linux/man-pages/man8/ifconfig.8.html

and "ping" command manual:

https://man7.org/linux/man-pages/man8/ping.8.html

 

ps. When you see Windows tutorial "how to solve some problem", you can still use that knowledge on Linux or whatever else, just use "what is equivalent of XXX on linux/whatever" as search keyword..

e.g. https://www.google.com/search?q=ifconfig+gateway

I see user answered that "ifconfig" is depreciated, and user should use "ip" instead... So:

https://man7.org/linux/man-pages/man8/ip.8.html

and

https://www.google.com/search?q=ip+command+linux+examples

Quote

Any idiot-proof guidance to cure the misbehavior will be appreciated.

Forget it. The problem is unknown. e.g. somebody (hacker) could give you fake DNS servers (because intercepted your router).. so you may be connecting to his/her machine, instead of true DNS servers.. Or somebody in company which is providing you net, is restarting DNS servers, or they are restarted automatically every xxx minutes/hours to update for new DNS records... Even if you may be connected via cable Ethernet, it does not guarantee that your ISP provider does not use radiowave Internet further in route. e.g. if there is bad weather (i.e. snow especially), radio Internet has issues, because snowflakes and raindrops with heavy wind reflects signal (I always have problems with net (LTE, WiFi) during heavy snow or heavy rain).

You can detect if you DNS servers have been intercepted by hacker. How? Learn what are DNS servers that your computer is using, and search that IP in Google. Or use reverse-DNS on that IP address. Results should show that they are legit DNS servers of ISP that you're using (big ISP providers mention what are their DNS servers on their websites).

This subject is so huuge, that your asking to give idiot-proof tutorial, is like asking to give idiot-proof tutorial of surgery of brain, but on steroids..

 

 

If you find that your ISP DNS is down by pinging it (better be prepared to in advance), but pinging Google DNS servers work.. you can change DNS servers to Google DNS e.g.

https://www.google.com/search?q=how+to+set+dns+linux

 

Edited December 28, 2020 by Sensei

[Ghideon]

3 minutes ago, Sensei said:

Any network admin will tell you "if your own DNS don't work, use Google DNS". So better remember their IPs in advance..

@Externet I have quickly read through Sensei's answer and he has posted the full description of what I had in mind but I intended to move step by step. You may skip by questions look at Sensei's steps first.

Note: My router had the option for a manual DNS-server entry in addition to the DNS server ISP provided via DHCP; adding google's DNS 8.8.8.8 as the secondary DNS server helped in a case where the ISP had issues.

[Externet]

1 hour ago, Ghideon said:

Questions: 
-All internet connected equipment at your home gets the problem, all gets the problem at the same time?  ----> Not always, sometimes one of three, sometimes two of three.
-How is the router (modem) connected to internet? ----> Coaxial cable to the utility pole is as much as I can tell.

Utility pole--------coax---------F connector gateway------four RJ45 jacks, 3 used to each of 3 devices with no splices of any kind and in unmolested new condition less than 6 metres length.

-What happens if you power-cycle the gateway when problem occurs, does that fix the issue? ----> Not always. sometimes fixes one device, sometimes fixes one and impairs another.

powering off also the devices seems to work better to restablish functionality; unsure if simoultaneity or which one delayed (device or gateway)

 

Thanks.

Following Sensei suggestion will take longer for me to digest.  Will put good effort to understand it, even no Windows here.

 

At the moment, this computer is working normal interacting with scienceforums; the tuner is showing live RAI (Italia) broadcast news but the Chromebook complains about DNS probe.failed.

[MigL]

I have AVG ant-virus on some of my Win10 computers, and when AVG does an update, it locks me out of internet access, for some reason. Eventually, it crashes my connection to the router/modem.
I have given up trying to find the problem, and simply disconnect power to the router/modem, and let them re-establish the network.
My 'house' phone is an internet phone, so when I've got no dial tone, I know there's a problem with the network.

Maybe I should just switch all my computers to Avast anti-virus, as they don't seem to give me any problems.

[Ghideon]

18 minutes ago, Externet said:

Not always. sometimes fixes one device, sometimes fixes one and impairs another.

Ok. I recommend taking a look at Sensei's post. Ask further questions if you get stuck.

One thing: When one computer has the DNS problem, can you still surf to the web page https://8.8.8.8 ? (Google's DNS server via IP address instead of the DNS name) 

Since you seem to have the issue also on the tuner I would look at issues with the router first.

Edited December 28, 2020 by Ghideon

[Externet]

Thanks MigL. I do not know what an antivirus is.  Have not had such since 2005 when abandoned Windows.

[Sensei]

24 minutes ago, Externet said:

Following Sensei suggestion will take longer for me to digest.  Will put good effort to understand it, even no Windows here.

Problems are universal. Just commands/tools have different names with different arguments.. Tutorial made for one OS will work with other OS if you will look up what is equivalent command on different OS.

[Externet]

Thanks Ghideon.  I can access the gateway 'reports' at 192.168.100.1 if that means anything.   Typing https://8.8.8.8 at address responds as "is unreachable"

[Sensei]

10 minutes ago, Ghideon said:

One thing: When one computer has the DNS problem, can you still surf to the web page https://8.8.8.8 ? (Google's DNS server via IP address instead of the DNS name) 

Good advice +1. Easier for newbie.

 

2 minutes ago, Externet said:

Thanks Ghideon.  I can access the gateway 'reports' at 192.168.100.1 if that means anything.   Typing https://8.8.8.8 at address responds as "is unreachable"

ping it in terminal (or equivalent) instead..

ping other machine from your LAN (to see if it is reachable). And vice versa from other machine to yet another machine.

(learn what are IPs of the all machines in your LAN first)

(on some devices, they can have disabled ICMP packets so ICMP ping won't work at all unless you use TCP/IP ping and/or enable ICMP ping manually)

 

Edited December 28, 2020 by Sensei

[Ghideon]

1 minute ago, Externet said:

I can access the gateway 'reports' at 192.168.100.1 if that means anything.

Good; means we can rule out issues between that equipment and the router.

 

1 minute ago, Externet said:

Typing https://8.8.8.8 at address responds as "is unreachable"

Ok!

Do you know how to open a terminal window and type commands? If so, type in:

ping 8.8.8.8 

If there are intermittent errors an external address such as googles DNS (8.8.8.8) would look like this:

>ping 8.8.8.8   
PING 8.8.8.8 (8.8.8.8): 56 data bytes
64 bytes from 8.8.8.8: icmp_seq=10 ttl=118 time=13.940 ms
64 bytes from 8.8.8.8: icmp_seq=11 ttl=118 time=13.774 ms
64 bytes from 8.8.8.8: icmp_seq=12 ttl=118 time=23.898 ms
ping: sendto: No route to host
Request timeout for icmp_seq 13
ping: sendto: No route to host
Request timeout for icmp_seq 14
Request timeout for icmp_seq 15
64 bytes from 8.8.8.8: icmp_seq=16 ttl=118 time=125.050 ms
64 bytes from 8.8.8.8: icmp_seq=17 ttl=118 time=4.924 ms

Note the timeouts above, they hint that there is a connection issue at that time. In this case I intentionally disconnected from the network to get this error.

If you ping your router instead of (ping 192.168.100.1 instead of ping 8.8.8.8 since I guess 192.168.100.1 is the address of your router)  there would be no timeouts unless there is an internal issue in your network.

 

 

[Sensei]

15 minutes ago, Ghideon said:

One thing: When one computer has the DNS problem, can you still surf to the web page https://8.8.8.8 ? (Google's DNS server via IP address instead of the DNS name) 

..If I visit  https://8.8.8.8  it automatically converts to https://dns.google/ ... (some kind forwarder)

If you can check it: make your DNS unreachable in router (i.e. wrong IP data), then visit  https://8.8.8.8  to see what happens...

 

Just now, Ghideon said:

If you ping your router instead of (ping 192.168.100.1 instead of ping 8.8.8.8 since I guess 192.168.100.1 is the address of your router)  there would be no timeouts unless there is an internal issue in your network.

Yeah... On Windows you should use "ping [IP] -t" and leave it.. and if Ethernet cable has problems i.e. is physically damaged e.g. by walking on it... having it through doors which are frequently closed and opened and similar things.. basically damaged cable.. then in such a case, continuous ping will have some lost packets..

 

[Externet]

Side question... DNS is like a telephone directory, where names are shown as their equivalent numbers; example scienceforum.net is 153.229.14.32 or something like that.

And if the DNS is kaput, if I know and type instead of scienceforums.net that IP address "153.229.14.32" I should arrive to this site, right ?

Sorry,  am  s l o w .

I do not know how to find the 'numerical' IP address of devices or sites.😪

Thanks... I will now try the suggestions on last 2 posts.

[Ghideon]

8 minutes ago, Sensei said:

.If I visit  https://8.8.8.8  it automatically converts to https://dns.google/ ... (some kind forwarder)

Good catch! I can't disable my DNS at this time, did a quick check with Curl to verify your comment:

(... means I removed logs not necessary for this discussion)

curl -v https://8.8.8.8
*   Trying 8.8.8.8...
* TCP_NODELAY set
* Connected to 8.8.8.8 (8.8.8.8) port 443 (#0)
...
subjectAltName: host "8.8.8.8" matched cert's IP address!
*  issuer: C=US; O=Google Trust Services; CN=GTS CA 1O1
*  SSL certificate verify ok.
...
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="https://dns.google/">here</A>.
</BODY></HTML>
* Connection #0 to host 8.8.8.8 left intact
* Closing connection 0

 

[Sensei]

21 minutes ago, Externet said:

And if the DNS is kaput, if I know and type instead of scienceforums.net that IP address "153.229.14.32" I should arrive to this site, right ?

Physical HTTP server can have virtual servers. They share the same IP address. But have different "host name".

If we have custom made server, with HTTP like Apache installed, and we are alone, it would work, http://our_ip and http://hostname will give the same (because no Virtual Servers are configured https://en.wikipedia.org/wiki/Virtual_hosting )

but most of HTTP servers these days, are hosted on 3rd party machines i.e. clouds in server rooms in foreign country.

And single IP has multiple (e.g. thousands) virtual servers on it..

You can learn what are these virtual servers by using reverse-DNS (search net for keyword)

Edited December 29, 2020 by Sensei

[Ghideon]

11 minutes ago, Externet said:

Thanks... I will now try the suggestions on last 2 posts.

In case you find an issue with the DNS and need to add a secondary / temporary one: try to Google "how to set google dns in router modem XYZ" (replace router modem XYZ with your brand and model) 

One more: You can also check your ISP's web page or support forum if there are known issues on their side (or twitter or whatever channel they use to communicate issues)

 

[Sensei]

18 minutes ago, Externet said:

And if the DNS is kaput, if I know and type instead of scienceforums.net that IP address "153.229.14.32" I should arrive to this site, right ?

IP "153.229.14.155" is in Japan.

For me "scienceforums.net" resolves to "94.229.79.58"..

 

[Externet]

Cannot find the 'terminal' nor a 'console' in this one week new Chromebook, an unskilled with it. 

Am  s l o w   to remind your kindness. Will be back after follow suggestions above.

[Sensei]

1 minute ago, Externet said:

Cannot find the 'terminal' nor a 'console' in this one week new Chromebook, an unskilled with it. 

Am  s l o w   to remind your kindness. Will be back after follow suggestions above.

https://chromium.googlesource.com/chromiumos/docs/+/master/developer_mode.md

 

[Externet]

Thanks for your patience.  Will follow.

Typing 94.229.79.58 responds as "is unreachable" on the Chromebook; 😪 and on the Linux machine am now; shows

 

Edited December 29, 2020 by Externet

[Sensei]

4 minutes ago, Externet said:

Thanks for your patience.  Will follow.

Typing 94.229.79.58 responds as "is unreachable" 😪

How about you @Ghideon and @MigL .... ? Repeat above..

45 minutes ago, Sensei said:

(learn what are IPs of the all machines in your LAN first)

On Windows, you can do it using command "arp -a".

https://www.google.com/search?q=arp+on+linux

https://man7.org/linux/man-pages/man8/arp.8.html

and

https://man7.org/linux/man-pages/man8/route.8.html

 

11 minutes ago, Externet said:

Typing 94.229.79.58 responds as "is unreachable" on the Chromebook; 😪 and on the Linux machine am now; shows

Because you can't visit HTTPS via IP address.. It has no info about SSL certificates which are given to specific "host name"..

Additionally, like I said, server with IP 94.229.79.58 has multiple other websites..

https://ipinfo.io/94.229.79.58

 

 

[Sensei]

3 hours ago, Externet said:

I do not know how to find the 'numerical' IP address of devices or sites.😪

Simply open terminal/shell/console, and ping giving name e.g.

ping google.com

ping scienceforums.net

and in output will be numerical IP address, like on my screen-shot above.

You can select it in console and copy (either on Windows and Linux)

Edited December 29, 2020 by Sensei

[Ghideon]

10 hours ago, Sensei said:

How about you @Ghideon and @MigL .... ? Repeat above..

% ping scienceforums.net
PING scienceforums.net (94.229.79.58): 56 data bytes
64 bytes from 94.229.79.58: icmp_seq=0 ttl=53 time=38.113 ms
64 bytes from 94.229.79.58: icmp_seq=1 ttl=53 time=46.938 ms
64 bytes from 94.229.79.58: icmp_seq=2 ttl=53 time=46.979 ms
64 bytes from 94.229.79.58: icmp_seq=3 ttl=53 time=46.788 ms
^C
--- scienceforums.net ping statistics ---
6 packets transmitted, 6 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 38.026/49.386/79.470/14.022 ms

 

[Externet]

Poking, resetting, changing parameters, trying other servers, cycling power of all devices in different sequences...  the Linux computer on Rj45-1 ended impaired too.  No internet for a couple of days, unable to post.  Interestingly, the internet television tuner on the RJ45-3 was always able to work fine.

 Removed the RJ-45-2  Ethernet-to-USB adapter below from the Chromebook and restored functionality on this, the Linux unit. Posting the progress.  Seems the adapter is flaky or kaput. Worked fine just for a few days.