[ SOLVED ] No DNS cache

[Wirezfree]

@paul1149
Do you have Chrome Browser installed.??
IIRC it will only show results if it detects you have Chrome browser default.??

[paul1149]

Done. Sorry, I forgot about that.

[torreydale]

paul1149,

In reply #5, you mentioned you think this is solved.  If so, could you mark this thread as such?

[paul1149]

Wirez: I gave namebench a spin (I ran it when the problem first arose as well). But I don't see any report. It ran twice in GUI mode, finally I killed it, with nothing to show for it. I did run raw pings on the nameservers back then, and found them all close in speed.

Fire: I found the 'mdns4" spec missing from that line and added it. Otherwise the desired order was already there. I think I'd like to leave IP6 in place, as soon it probably will be necessary.

Thanks guys.

[firenice03]

One other to try...


Check  /etc/nsswitch.conf  file... Look for..

Code: [Select]

hosts:          files mdns4_minimal [NOTFOUND=return] wins dns mdns4
Within that line, "wins" is mentioned..
Change the order to:

Code: [Select]

hosts:          files mdns4_minimal [NOTFOUND=return] dns mdns4 wins

As suggested here:
http://ubuntuforums.org/showthread.php?t=1904264&page=2

Update: Another thought
Something else to try, try turning off IPv6
How to disable: http://askubuntu.com/questions/440649/how-to-disable-ipv6-in-ubuntu-14-04

[Wirezfree]

If you are feeling really geeky,
and want to test dns out.??

namebench is available in synaptic...

[paul1149]

Yes, all the machines funnel through the same router, where I manually spec three DNS servers.

Good info at that page. Thank you.

Funny, but the only two sites that still consistently hang on DNS lookup are this one (LL) and ask.libreoffice.com. Everything else seems fine. Not sure why this is, as DNS has nothing to do with remote server speed.

[firenice03]

Absolutely awesome, firenice. I ran the install, which went well and auto-started the service. Even without a reboot, now when I first visit a domain I get the "resolving host" delay. But subsequent visits are without delay. I dare say we've got this beat!

I suppose I did a "complete removal" of some software a couple of months ago and it must have taken NSCD out with it.

Thanks much, and blessings!

Not a problem, good to hear its getting you closer 

Do the Windows and Linux boxes use the same DNS servers?? You mention Linux having slower resolution..
Maybe try manually entering the windows IP's on the Linux box.

This link is the same info torreydale provided but has some additional info should it help...
http://askubuntu.com/questions/272358/extrememly-slow-dns-lookup

[paul1149]

Thanks. I do remember doing a complete removal, but what prog it was is lost at this point. I doubt I used the LL SW tool. I'm surprised synaptic doesn't distinguish between critical base services and other software.

[technomancer]

(I have a similar issue with Xerox automatic meter reporting on copiers. DNS can be tricky !)

A complete uninstall of software can lead to issues i have found. Some not so obvious.
If you used synaptic package manager it may have taken out a DNS related component as you suspect.
Selecting complete removal sometimes does not differentiate between critical packages.



However if you used the LinuxLite SW tool, I am sure Jerry would like to know so the issue can be addressed.

[paul1149]

I rebooted, and the problem is still resolved. I would say there is a bit more time spent resolving hosts than before the reboot, but most of the time it is later in the page load sequence, indicating the DNS's of secondary, remote elements being sought out. I think it's solved.

[paul1149]

That's interesting, Torrydale. If I understand it, resolv.conf tells the programs to look to the machine for the DNS nameserver, and then the machine tells it to look to the network settings? In my case, I then send the request to the router, rather than to the default ISP nameserver.

If I were to do this, I would use OpenDNS rather than google, though, since I don't want google to know every site I look up. I'll watch my current situation for a while, but the nscd install seems to be 99% on the money so far.

[torreydale]

I had a similar DNS head scratcher when I connected to my personal OpenVPN Access Server.  There is something unusual with how Linux Lite handles DNS.  Perhaps firenice03's suggestion is on to something.  The workaround to my issue is below. 

What is the result you get from the following?:

Code: [Select]

sudo nano /etc/resolv.conf
If the nameserver you see is 127.0.0.1, change the line that states nameserver 127.0.1.1 to nameserver 8.8.8.8

Then see if your results aren't better.  If they are better, when you reboot, the nameserver may return to 127.0.0.1.  As a workaround for this, to make the change stick, you'll have to add 8.8.8.8 as an Additional DNS Server in your Network Connections.  You'll find the Additional DNS Server settings under the IPv4 Settings tab of Network Connections (Menu > Settings > Network Connections).

8.8.8.8 is a Google public DNS server, by the way.

P.S.  You may also try to see what happens if you manually add your OpenDNS server IP addresses to the Additional DNS server settings, in addition to or instead of 8.8.8.8.  Use commas to separate multiple domain name server addresses.

UPDATE:  It's good to see firenice03's suggestion helped.  Can you reboot and report back whether your issue stays resolved after a reboot?

[paul1149]

Absolutely awesome, firenice. I ran the install, which went well and auto-started the service. Even without a reboot, now when I first visit a domain I get the "resolving host" delay. But subsequent visits are without delay. I dare say we've got this beat!

I suppose I did a "complete removal" of some software a couple of months ago and it must have taken NSCD out with it.

Thanks much, and blessings!

[firenice03]

You may need to install?? Since the error command not found...

Found this:
Install nscd using the following command if not yet

Code: [Select]

sudo apt-get install nscd
Flush DNS Cache in Ubuntu by restarting the nscd

Code: [Select]

sudo /etc/init.d/nscd restart
From here: http://askubuntu.com/questions/414826/how-to-flush-dns-in-ubuntu-12-04

Maybe worth a try to install???....

Added:
service nscd restart and sudo /etc/init.d/nscd restart are essentially the same command - restart said service (2 ways to accomplish the same)