CentOS - Feb 2017 - Spotty internet connection

How do you IT guys diagnose the problem with a spotty internet connection?

Just spent an hour on the phone with TWC/Spectrum. Of course they don't see
anything wrong with their service. 

They send me to speedtest.net. The first attempt, the page didn't fully
load, the second attempt, the page didn't load at all, the third attempt, it
loaded.

On a 20/2MB line I get 24.83/2.47MB. The speed is better than what I'm
paying for but its spotty.

Lately I have been getting slow  and partial page loads, server not found,
server timed out, etc.. Get knocked off ssh when accessing my home server
from work, etc. Its not the work connection because I don't have problems
accessing other sites, just here at home and my home server.

Is there any kind of utility to check for failing hardware?

TIA

On Thu, Feb 2, 2017 at 7:13 PM, TE Dukes <tdukes at palmettoshopper.com>
wrote:
> Lately I have been getting slow  and partial page loads, server not found,
> server timed out, etc.. Get knocked off ssh when accessing my home server
> from work, etc. Its not the work connection because I don't have
problems
> accessing other sites, just here at home and my home server.
>
> Is there any kind of utility to check for failing hardware?
I have the exact same problems from time to time via Comcast.  Mine
comes and goes, and lately it hasn't been too bad.  But when it comes,
it's down for very small amounts of time, maybe 30-90 seconds, which
is just long enough to be annoying, and make the service unusable.

When it was really bad (intermittent dropouts as described above,
almost every night during prime time, usually for several hours at a
time) I wrote a program to do constant pings to several servers at
once.  If you're interested, I'll see if I can find that script.  But,
conceptually, it ran concurrent pings to several sites, and kept some
stats on drops longer than some threshold.  Some tips on a program
like this: use IP addresses, rather than hostnames, because ultimately
using a hostname implicitly does a DNS lookup, which likely requires
Internet service to work.  I also did several servers at once, so I
could prove it wasn't just the one site I was pinging.  Included in
the list of servers was also the nexthop device beyond my house
(presumably Comcast's own router).  Use traceroute to figure out
network paths.

After running this for a while---before I called them with the
evidence---the problem magically cleared up, and since then it's been
infrequent enough that I haven't felt the need to fire up the script
again.  When it comes to residential Internet, I am quite cynical
towards monopoly ISPs like Comcast... so maybe they saw the constant
pings and knew I was building a solid case and fixed the problem.  Or
maybe enough people in my area complained of similar problems and they
actually felt uncharacteristically caring for a second.

I haven't been there in a while, but in the past, I've gotten a lot of
utility out of the DSLReports Forums[1].  There are private forums
that will put you in direct contact with technical people at your ISP.
It can sometimes be a good way to side-step the general customer
service hotline and get in touch with an actual engineer rather than a
script reader.  Maybe not, but worst-case you're only out some time.
Also, you might post this same question to one of the public forums
over there, as there seems to be lots of knowledgeable/helpful people
hanging out there.  (Despite the name, it's not only about DSL, but
consumer ISPs in general.)

[1] http://www.dslreports.com/forums/all

Good luck, let us know if you come up with any decent resolution!

> -----Original Message-----
> From: CentOS [mailto:centos-bounces at centos.org] On Behalf Of TE Dukes
> Sent: Thursday, February 2, 2017 6:13 PM
> To: 'CentOS mailing list' <centos at centos.org>
> Subject: [CentOS] Spotty internet connection
> 
> How do you IT guys diagnose the problem with a spotty internet connection?
> 
> Just spent an hour on the phone with TWC/Spectrum. Of course they don't
> see
> anything wrong with their service.
> 
> They send me to speedtest.net. The first attempt, the page didn't fully
> load, the second attempt, the page didn't load at all, the third
attempt, it
> loaded.
> 
> On a 20/2MB line I get 24.83/2.47MB. The speed is better than what I'm
> paying for but its spotty.
> 
> Lately I have been getting slow  and partial page loads, server not found,
> server timed out, etc.. Get knocked off ssh when accessing my home server
> from work, etc. Its not the work connection because I don't have
problems
> accessing other sites, just here at home and my home server.
> 
> Is there any kind of utility to check for failing hardware?
All depends where and what the fault is.

You can use wireshark to check for duplicate acknowledgements and
retransmissions, that's low hanging fruit.

Two recent issues I found that manifested in miserable browsing speed
where poor dns resolution speed (many tools exist to determine your
optimal forwarders or if you using the root hints it might expose this is
a less than optimal configuration) made for long pauses and a bad cable
for a user. The cable worked, and on the lan the retries made it seem like
there wasn't problem. Over the wan, the retries made everything painfully
slow.

> -----Original Message-----
> From: CentOS [mailto:centos-bounces at centos.org] On Behalf Of Matt
> Garman
> Sent: Thursday, February 2, 2017 8:52 PM
> To: CentOS mailing list
> Subject: Re: [CentOS] Spotty internet connection
> 
> On Thu, Feb 2, 2017 at 7:13 PM, TE Dukes <tdukes at
palmettoshopper.com>
> wrote:
> > Lately I have been getting slow  and partial page loads, server not
> > found, server timed out, etc.. Get knocked off ssh when accessing my
> > home server from work, etc. Its not the work connection because I
> > don't have problems accessing other sites, just here at home and
my home
> server.
> >
> > Is there any kind of utility to check for failing hardware?
> 
> I have the exact same problems from time to time via Comcast.  Mine comes
> and goes, and lately it hasn't been too bad.  But when it comes,
it's down
for
> very small amounts of time, maybe 30-90 seconds, which is just long enough
> to be annoying, and make the service unusable.
> 
> When it was really bad (intermittent dropouts as described above, almost
> every night during prime time, usually for several hours at a
> time) I wrote a program to do constant pings to several servers at once.
If
> you're interested, I'll see if I can find that script.  But,
conceptually,
it ran
> concurrent pings to several sites, and kept some stats on drops longer
than
> some threshold.  Some tips on a program like this: use IP addresses,
rather
> than hostnames, because ultimately using a hostname implicitly does a DNS
> lookup, which likely requires Internet service to work.  I also did
several
> servers at once, so I could prove it wasn't just the one site I was
pinging.
> Included in the list of servers was also the nexthop device beyond my
house
> (presumably Comcast's own router).  Use traceroute to figure out
network
> paths.
> 
> After running this for a while---before I called them with the
evidence---the
> problem magically cleared up, and since then it's been infrequent
enough
> that I haven't felt the need to fire up the script again.  When it
comes
to
> residential Internet, I am quite cynical towards monopoly ISPs like
Comcast...
> so maybe they saw the constant pings and knew I was building a solid case
> and fixed the problem.  Or maybe enough people in my area complained of
> similar problems and they actually felt uncharacteristically caring for a
second.
> 
> I haven't been there in a while, but in the past, I've gotten a lot
of
utility out
> of the DSLReports Forums[1].  There are private forums that will put you
in
> direct contact with technical people at your ISP.
> It can sometimes be a good way to side-step the general customer service
> hotline and get in touch with an actual engineer rather than a script
reader.
> Maybe not, but worst-case you're only out some time.
> Also, you might post this same question to one of the public forums over
> there, as there seems to be lots of knowledgeable/helpful people hanging
> out there.  (Despite the name, it's not only about DSL, but consumer
ISPs
in
> general.)
> 
> [1] http://www.dslreports.com/forums/all
> 
Thanks for the info.

I've seen that site before so I might check it out.

My router/modem has a log. Its loaded with errors I can't interpret. I
googled a portion of it and landed on TWC forums. 

Missing BP Configuration Setting TLV

http://forums.timewarnercable.com/t5/Connectivity/Predictable-disconnects/td
-p/1016

Didn't see much of an answer.

Hopefully it's a temporary thing as it just started.  I don't think
it's a
problem on my end, maybe, but doubt it. I'll give it another day or so.

Thanks!!

> -----Original Message-----
> From: CentOS [mailto:centos-bounces at centos.org] On Behalf Of Joseph L.
> Casale
> Sent: Thursday, February 2, 2017 8:58 PM
> To: 'CentOS mailing list'
> Subject: Re: [CentOS] Spotty internet connection
> 
> > -----Original Message-----
> > From: CentOS [mailto:centos-bounces at centos.org] On Behalf Of TE
Dukes
> > Sent: Thursday, February 2, 2017 6:13 PM
> > To: 'CentOS mailing list' <centos at centos.org>
> > Subject: [CentOS] Spotty internet connection
> >
> > How do you IT guys diagnose the problem with a spotty internet
> connection?
> >
> > Just spent an hour on the phone with TWC/Spectrum. Of course they
> > don't see anything wrong with their service.
> >
> > They send me to speedtest.net. The first attempt, the page didn't
> > fully load, the second attempt, the page didn't load at all, the
third
> > attempt, it loaded.
> >
> > On a 20/2MB line I get 24.83/2.47MB. The speed is better than what
I'm
> > paying for but its spotty.
> >
> > Lately I have been getting slow  and partial page loads, server not
> > found, server timed out, etc.. Get knocked off ssh when accessing my
> > home server from work, etc. Its not the work connection because I
> > don't have problems accessing other sites, just here at home and
my home
> server.
> >
> > Is there any kind of utility to check for failing hardware?
> 
> All depends where and what the fault is.
> 
> You can use wireshark to check for duplicate acknowledgements and
> retransmissions, that's low hanging fruit.
> 
> Two recent issues I found that manifested in miserable browsing speed
> where poor dns resolution speed (many tools exist to determine your
> optimal forwarders or if you using the root hints it might expose this is
a less
> than optimal configuration) made for long pauses and a bad cable for a
user.
> The cable worked, and on the lan the retries made it seem like there
wasn't
> problem. Over the wan, the retries made everything painfully slow.
Thanks,

My first thought it might be a dns issue. I may change to googles dns
servers and see if things improve.

This just started in the last couple days. I know TWC and Charter are
merging, but this is irritating.

I'll check out wireshark.

> How do you IT guys diagnose the problem with a spotty internet connection?
> Just spent an hour on the phone with TWC/Spectrum. Of course they don't
see
> anything wrong with their service. 
> They send me to speedtest.net. The first attempt, the page didn't fully
> load, the second attempt, the page didn't load at all, the third
attempt, it
> loaded.
> On a 20/2MB line I get 24.83/2.47MB. The speed is better than what I'm
> paying for but its spotty.
> Lately I have been getting slow  and partial page loads, server not found,
> server timed out, etc.. Get knocked off ssh when accessing my home server
> from work, etc. Its not the work connection because I don't have
problems
> accessing other sites, just here at home and my home server.
> Is there any kind of utility to check for failing hardware?
> TIA
Another thing to check is the wiring to the house.  If this is a cable company,
it is likely that the cable to the cable modem splits off to the TV(s).  Make
sure there are not any unterminated co-ax cable which used to go to a TV.  Make
sure the cable outside the house is not damaged.  The cable company can test for
bad cable at your location.  They may charge for this.  You could get a length
of co-ax and swap it in in various places to see if the problems go away.
 

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On 2/3/2017 4:38 AM, Styma, Robert (Nokia - US) wrote:
> Another thing to check is the wiring to the house.  If this is a cable
company, it is likely that the cable to the cable modem splits off to the TV(s).
Make sure there are not any unterminated co-ax cable which used to go to a TV. 
Make sure the cable outside the house is not damaged.  The cable company can
test for bad cable at your location.  They may charge for this.  You could get a
length of co-ax and swap it in in various places to see if the problems go away.
if you have multiple splitters, make sure the cable modem is on the 
'first' one, and that splitter is a high grade 2-way one. Make sure all 
cable is high grade RG6 quad shield and not older RG59 or whatever.


-- 
john r pierce, recycling bits in santa cruz