Resolving Host...

My laptop WiFi connection has been completely trouble-free until
recently. Now, it's nothing but trouble. It takes several
attempts to connect to my AP and even if it connects successfully
it often fails to resolve names. I see it with Chrome, but
other apps--mail, etc--are failing the same way.

I've tried DHCP for nameserver assignment and have tried
manually plugging them in. No difference. Sometimes, things
work for a few minutes and then resolution problems set in.

I thought that IPV6 might be causing trouble, but getting
rid of it doesn't make any difference.

What should I look for?

On Fri, 28 Jul 2017 17:37:49 -0400, Jason
wrote:

My laptop WiFi connection has been completely trouble-free until
recently. Now, it's nothing but trouble. It takes several
attempts to connect to my AP and even if it connects successfully
it often fails to resolve names. I see it with Chrome, but
other apps--mail, etc--are failing the same way.

I've tried DHCP for nameserver assignment and have tried
manually plugging them in. No difference. Sometimes, things
work for a few minutes and then resolution problems set in.

I thought that IPV6 might be causing trouble, but getting
rid of it doesn't make any difference.

What should I look for?

You should look for an Ethernet cable and use it to connect your laptop
to your router, thus ruling out or confirming whether WiFi is the
problem.

That's my cutesy way of saying it sounds like a WiFi issue rather than a
DNS issue. Once you know for sure, you can troubleshoot appropriately.

Another angle would be to take the laptop somewhere else, such as a
library or McD's, to see how it works there. If there are no such
issues, the problem is likely to be at your house, whether interference
or bad hardware (WiFi router), etc.

[This followup was posted to alt.comp.os.windows-10 and a copy was sent
to the cited author.]

In article ,
lid says...
That's my cutesy way of saying it sounds like a WiFi issue rather than a
DNS issue. Once you know for sure, you can troubleshoot appropriately.

Another angle would be to take the laptop somewhere else, such as a
library or McD's, to see how it works there


I would conclude it's a WiFi issue too if it weren't for the
fact that we have a number of other devices--phones, another
laptop, a couple printers that all seem ok. I'm suspicious of
the router for no particularly good reason. The new generation
of mesh network routers looks intriguing and this one's getting
old. I wish I could borrow one of the new ones to see how it
compares.

"Jason" wrote

| I would conclude it's a WiFi issue too if it weren't for the
| fact that we have a number of other devices--phones, another
| laptop, a couple printers that all seem ok. I'm suspicious of
| the router for no particularly good reason. The new generation
| of mesh network routers looks intriguing and this one's getting
| old. I wish I could borrow one of the new ones to see how it
| compares.

A shot in the dark, but two things that come to mind:

1) Flush the DNS cache.

https://www.megebyte.com/how-to-clea...in-windows-10/

Windows has one. Browsers and DNS proxies can also
have them. Assuming you don't use a DNS proxy, and if
it's not just one program, then suspicion falls to Windows.
It's possible that some IPs have been switched around and
your Windows cache is out of date. (Though I've only
ever seen the problem with my proxy server cache.)

2) Check your DNS server setting. Ideally it's pointing to
something like OpenDNS and not your ISP or other
commercial entity. If you're not sure you can always
try switching. OpenDNS:

208.67.220.220
208.67.222.222

I'm confused by the DHCP comment, though. DHCP is
for getting an IP address from behind the router, when
you don't used a fixed IP. By nameserver I assume you
mean DNS, which is a remote host you contact to get
the IP address for a URL, in order to contact that server.

On Fri, 28 Jul 2017 21:06:52 -0400 "Mayayana"
wrote in article



A shot in the dark, but two things that come to mind:

1) Flush the DNS cache.

https://www.megebyte.com/how-to-clea...in-windows-10/

Windows has one. Browsers and DNS proxies can also
have them. Assuming you don't use a DNS proxy, and if
it's not just one program, then suspicion falls to Windows.
It's possible that some IPs have been switched around and
your Windows cache is out of date. (Though I've only
ever seen the problem with my proxy server cache.)

Does this cache persist across boots?


2) Check your DNS server setting. Ideally it's pointing to
something like OpenDNS and not your ISP or other
commercial entity. If you're not sure you can always
try switching. OpenDNS:

208.67.220.220
208.67.222.222

I have done this - overriden the default automatic behavior by
aiming the machine at those (and Google's) DNS servers. Didn't make
a difference.


I'm confused by the DHCP comment, though. DHCP is
for getting an IP address from behind the router, when
you don't used a fixed IP. By nameserver I assume you
mean DNS, which is a remote host you contact to get
the IP address for a URL, in order to contact that server.
That's what I understand a nameserve to be. I thought it was
assigned by my ISP by the same mechanism as for acquiring an
IP address.

On 28 Jul 2017, Jason wrote in
alt.comp.os.windows-10:

My laptop WiFi connection has been completely trouble-free until
recently. Now, it's nothing but trouble. It takes several
attempts to connect to my AP and even if it connects successfully
it often fails to resolve names. I see it with Chrome, but
other apps--mail, etc--are failing the same way.

I've tried DHCP for nameserver assignment and have tried
manually plugging them in. No difference. Sometimes, things
work for a few minutes and then resolution problems set in.

I thought that IPV6 might be causing trouble, but getting
rid of it doesn't make any difference.

What should I look for?

Interesting that you should mention this. I was having what sounds like
the same problem for 4 or 5 days prior to last Tuesday. All web
browsers had great difficulty reaching their targets. Connections to
email servers was tenuous, with frequent time-outs. File transfers
would stall out. Things seemed to be getting worse over the course of
those days. All other wireless devices in the house were working as
usual.

I thought my antivirus (Avast) might be the problem, so I uninstalled
it. I turned off Windows firewall. I turned off IPv6. I changed the DNS
server to something other than my ISP's. I examined Windows' event logs
for clues. I examined my router's log for errors. Nothing helped. The
only thing that seemed slightly amiss was that Windows Defender hadn't
been updated since April. Since Avast was installed, I didn't think
that mattered, although I had been assuming WD would have still been
updated, even if not in active use.

I wondered if the laptop's wifi adapter was failing, so I connected the
laptop via Ethernet. Suddenly, WD updated itself via Ethernet, and
since then (3 days and counting) wifi has been back to normal!

So, either it was a router/ISP issue that happened to be fixed at just
the right time, or somehow Defender was messed up and updating it fixed
things. Another idea I had is that a recent Avast update messed
something up with Defender, but that doesn't quite explain why it took
uninstalling Avast and updating Defender to repair things (if indeed it
did.) Otherwise, I have no other possible explanations.

All's well that ends well... until the next time.

"Jason" wrote

| Does this cache persist across boots?
|

I don't know. You could look it up. Or you could
just clear it. As I said, I've only seen cache cause
problems with my proxy (Acrylic), and that
was only once, so I know the proxy cache persists.
Windows cache may not. And I know Firefox has a
cache but I don't know how long that persists. I have
it set to 0.

| I'm confused by the DHCP comment, though. DHCP is
| for getting an IP address from behind the router, when
| you don't used a fixed IP. By nameserver I assume you
| mean DNS, which is a remote host you contact to get
| the IP address for a URL, in order to contact that server.
| That's what I understand a nameserve to be. I thought it was
| assigned by my ISP by the same mechanism as for acquiring an
| IP address.
|

The ISP gives you an IP address to connect through.
The router has a local IP address for each machine.
So you might be at 100.100.200.200 when you check
online. Locally, at your specific machine, you're probably
something like 192.168.1.50. That can be dynamically
assigned by the router via DHCP or you can set
fixed IP addresses within the range the router
accepts. (I use fixed IP only so that I can disable
DHCP, so that I don't have anything running under
svchost and therefore don't have to allow anything
Microsoft through the firewall.)

A nameserver usually refers to DNS. Domain Name
Server. A HOSTS file is also a nameserver of sorts.
You try to go to somewhere.com. Your browser
checks for that in HOSTS and maybe in the browser
cache. Then there's the Windows cache. I don't
know the details of that. Maybe someone else does.
I do know there's a DNS client service, which I keep
disabled. The description seems to indicate that it's
necessary for Active Directory, but since I'm not on
a network I don't enable it.

Assuming somewhere.com was not found in any of
those places, a call will be made to your selected DNS
server to get the IP address of somewhere.com. It's
analogous to phone numbers. You can't call Ed Smith.
You can't visit somewhere.com. You have to call
212-555-1212 or visit 100.100.200.200. DNS is the
Internet's phone book.

Your ISP may sometimes assign DNS. That's a typical
trick to allow them to do things like show you an ad in
place of a 404 response. But you don't have to use your
ISPs DNS. You can set any that's available.

But it sounds like those two possibilities -- DNS cache
and DNS server -- are not your problem. They were just
longshot ideas that I thought were worth ruling out.

On Fri, 28 Jul 2017 17:37:49 -0400, Jason wrote:

What should I look for?

Go to the laptop makers website and download the latest drivers for the
WiFi adaptor. Delete the current driver in Device Manager and reboot.
Load the new drivers.

Alternately, figure out who makes the adaptor for your laptop
manufacturer and get the latest drivers from their site. I had a Dell
desktop with Dell's latest drivers that kept dropping connections.
Downloaded from the manufacturers website and things fixed right up.

Belarc Advisor is a good way to enumerate hardwa
http://www.belarc.com/products_belarc_advisor

--

-Jeff B.


"Excuse me.
I don't mean to impose,
but I am the Ocean."

~ The Salton Sea