Netflix problem

[heady6]

Hi

A few weeks ago Netflix stopped working properly on certain devices. We use netflix via the ps4, ipads and phones. Our main way of watching it is with the ipad though. Now, on the ipads, the netflix app loads, you can choose your profile etc, but as soon as you try and watch a show you get the spinning wheel. If you do the same series of events on the ps4 it works OK. The ps4 is wired to the hub, the ipad isnt. 

I've tried doing a factory reset on the hub, have called netflix and have attempted all the diagnostics, but with no success. Anybody have any ideas?

Thanks

Dave

[gary_dexter]

If it’s working on one device but not another then it’s not a network issue. It would point to a device issue. 

[jbrennand]

So its working fine on a wired device but not over wifi phones - so how do other apps like Youtube videos perform on those wifi devices?

[sophist]

Similar problem reported here https://community.virginmedia.com/t5/Networking-and-WiFi/Netflix/td-p/4452402

From the troubleshooting I did, I believe that it's an issue with the Virgin Media hosted Netflix CDN servers.. it's difficult to go much further without understanding what's happening when the traffic leaves my network and enters the Virgin network.. 

@gary_dexter -  "it's not a network problem".. i disagree.

Different devices get pointed at different CDN servers - it's entirely possible that it will work for one device but not another because the CDN servers that they are pointed at to stream the content are different..

[gary_dexter]

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@sophist wrote:

Similar problem reported here https://community.virginmedia.com/t5/Networking-and-WiFi/Netflix/td-p/4452402

From the troubleshooting I did, I believe that it's an issue with the Virgin Media hosted Netflix CDN servers.. it's difficult to go much further without understanding what's happening when the traffic leaves my network and enters the Virgin network.. 

@gary_dexter -  "it's not a network problem".. i disagree.

Different devices get pointed at different CDN servers - it's entirely possible that it will work for one device but not another because the CDN servers that they are pointed at to stream the content are different..

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Post some evidence to support this. 

[sophist]

happy to - though it'll have to wait until this evening.. 

from the packet captures i did the other day - when I am sent to 62.252.5.25 to stream content everything works perfectly.  When I am sent to 62.252.5.21 to stream content, (which I assume is in the same subnet as .25) all I get is a bunch of retransmits and no response from the server.  I am unable to talk to .21 on port 443 from within my network but am able to talk to .25.

there's another address in the equation which I can't talk to either - 81.100.3.0 - again, sending packets to it but no response and lots of retransmits. 

From outside the VM network, I am able to connect to both 81.100.3.0 and 62.252.5.21 on port 443.  62.252.5.21 is a VM hosted netflix CDN server (if the PTR record is anything to go by...) but 81.100.3.0 has no PTR record, so no idea what it does, but that's where my iOS devices get pointed at when initiating a stream.

[sophist]

It's also worth adding that none of my iOS devices have a problem streaming from Netflix if I send the traffic down a VPN to a termination point outside the VM network - so it absolutely isn't a device issue.

This setup uses the same internal network infrastructure (access points, switches, router) as when trying to stream directly over my VM connection, it's just that my router routes the data down a VPN rather than breaking out of the default gateway directly onto virgin's network. 

apologies - couldn't edit my previous post to add this comment for some reason..

[sophist]

@gary_dexter as requested, supporting evidence attached.

This is an image of a packet capture capturing all network traffic going in and out of my iPhone (.122).  As you can see - the two IP addresses I mention in the previous post are not responding to any requests. my phone attempts a three-way-handshake but never gets a response, it retransmits several times before timing out and re-initiating the connection, only to end up retransmitting several times again.

there's some other traffic in there that's not particularly relevant, other than to show it's quite happy to talk with other hosts on the internet.. 

The next image, is me initiating a connection to the CDN on port 443 - the top half of the image is from my router at home, the bottom half of the image is from a server outside the Virgin media network.. I am unable to initiate a connection from the public IP address interface of my router - i.e. no NAT involved here.. 

My best guess, is that someone has fatfingered some configuration on a router/switch between me and this server - perhaps an ACL, perhaps some sort of IDS/IPS - I can only speculate since traceroute is useless - perhaps I'll install tcptraceroute and see if that gives any more info.. 

either way, currently I'm sending packets to some IP addresses that belong to Virgin Media, are where my Netflix clients are being told by the Netflix CDN to go download the content from, and I am unable to establish a connection to them..

[sophist]

another interesting screenshot below - this shows a tcptraceroute to a working CDN node (.25) and the same again to the one that isn't working for me.. 

three hops to the working one

got bored after 17 hops on the other one.

it can't be an issue with the routing table, since .21 and .25 have to be in the same subnet.. unless VM are using /29's or /30's to carve up space for these sorts of things.. possible i suppose, but feels very unlikely. . so it's either an issue with the server itself  - or an issue with the switchport that the server connects to..? bleh. clutching at straws and without anyone to look at the traffic from the other end, this will go nowhere.

Hopefully the forum team stumbles across this sometime and mentions it to one of their network engineers.. 

[sophist · Accepted solution]

Grr, i ran out of time to edit the previous message..

so, on further investigation, it does actually seem possible/plausible that they are using /30's for these networks.. so it could be a routing issue after all

I tested connectivity to a few more IP addresses in proximity to these - all of which (at least from reverse name lookups) appear to be netflix cdn's dotted around the country.. i was able to successfully connect to .19, .25, .27, .29, .31, .33 & .35 but NOT .21 and .23.

Based on the reverse lookups, and making some assumptions about their naming convention, .21, .23, .25 and .27 are all hosted down at Aztec West, near Bristol - which makes sense for me geographically.. 

@OP - are you somewhere within a ~50 mile radius of Bristol?