We manage this website: http://elearning.uem.mz
It is from mozambique (hosted in Portugal), and we have a lot of complaints that the users can't connect to it.
It seems to be a problem with the connection from the user, but we can't pinpoint the exact problem.
What we know is:
It affects randomly (a computer works one day, the next it doesn't);
It seems based on time (a user won't be able to connect for 30 minutes to 2 hours);
Sometimes it gives a Privoxy 500 Error;
Sometimes it gives ERR_NAMES_NOT_RESOLVED;
It affects all browsers.
We created a small .bat script that has to be run as administrator:
ipconfig /flushdns
ipconfig /renew
ipconfig /registerdns
This seems to solve most times, but each issue has to handled individually.
Is there anything we could do to minimize this issue?
After a lot of time and testing, we found out that this was a problem happening to every other site in the respective country...
It seems to have been some problems/upgrades to the whole infra-structure that was, and still is, messing up most DNS.
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When I just start the pfSense, both Netflix and Prime works fine, I can login and watch contents, but after one day or so of my pfSense being online, I just can't login to those video streaming services anymore.
For Netflix I get the "NW-2-5" error and for Prime I receive a message saying there are connectivity issues. Then I have to reboot my pfSense and after that everything is working fine for, again, one day or so.
My guess is this has nothing to do with the firewall rules, as it works for one day or so, but just in case I took a screenshot of it, in the Block separator I isolated my other VLANs (Home, VPN BR and Guest):
I'm still learning about how to configure my pfSense correctly and I hope this is just a silly configuration mistake.
Any suggestion about what I should change or check in the configuration?
I use CheckPoint VPN to log in to my place of work's servers to work remotely. The VPN has been working (mostly) fine all year, and I haven't changed any of the settings, but this morning, when I tried to log in, it's giving me the "Arg_NullReferenceException." I can't seem to find anything on this particular error on google.
I have tried restarting my computer, because it's not the first issue I've had with CheckPoint VPN (though it is the first time I've seen that error message), and a restart usually resolves whatever issue I'm having. I've also tried creating a new connection with the same settings, but I'm getting the same error with that one, too.
I'm not entirely sure what other information I would need to provide. I'm also not sure if it's a problem on my end, or on the company servers. I have already emailed tech support, but I thought I should be thorough.
This is a known issue. I have been jumping through hoops trying to get the capsule client to work. Raise a ticket with TAC if you have support. If not then you can download the E86 Endpoint connect client and run it. That has been my work around for this issue.
They just issued an update to the Capsule via the Microsoft Store. It seems one of the recent Windows Security Update broke the L2TP protocol within windows.
Hey so I have three GCE instances set-up which all run the same code. They're cloned from the same snapshot so I'm pretty positive that they're exactly the same.
For some reason, only one of these GCE instances is able to receive connections from external sources. The other two can't. I keep getting a "Connection timedout" error in Firefox.
These instances all have the same network-tags, so they should have the same firewall rules. That is, if you're hitting this problem too, make sure you have the right firewall rules set in the networking tab of your google-cloud center before reading on.
Since they're running the same code and have the same ports open, I have no idea what the problem could be, or how to figure out what it might be.
I was wondering what the best way to debug this might be? I believe they were working earlier but now are no longer working.
Rebooting the instance seemed to fix this. This is not an adequate solution however. I'll update my answer over the coming weeks if it happens again.
I running an Ubuntu VM via Vagrant on a Windows 10 host. On the Vagrant machine I am running a fairly standard PHP/nginx app.
Whenever I try to access the web app, it takes forever to load. Chrome network inspector shows this:
Chrome network timeline
This huge latency is completely gone on subsequent requests, but whenever I pop back into the browser and try again after a while, it crops up yet again.
I am using NFS.
I have disabled firewalls on both guest and host machines.
I increased keepalive_timeout in nginx which helped hide the problem, as it increased the time window for latency-free subsequent requests.
This latency occurs even when accessing static files, so I don't think it's a PHP-FPM/MySQL problem.
I successfully figured out what my problem was!
After looking at my Windows hosts file, it looked like my vagrant-hostmanager plugin had not been properly clearing out older IP entries (i.e. I had three seperate IP entries for myapp.dev even though only one IP was active). Probably because I'd forgotten to properly vagrant halt before shutting down my PC a few times.
Windows was clearly spending ages trying to resolve the two older entries before successfully resolving the 'real' one.
It's weird: you'd think this problem would cause the latency to show up in the DNS Lookup portion of the Chrome network timeline, rather than Initial connection, but oh well!
I have a website running a basic ASP.NET application that is mostly used from a single location, which is my client's office. The server is at a high-class datacenter.
Whenever I've been testing or using my application from outside their office I have consistently good connections but from their office the connection seems inconsistent. Sometimes requests just don't seem to make it to the server from the browser. I'm not familiar with the network hardware in the office, but they do have a T1 connection which should always be on.
I've tried ping and tracert and everything looks normal. When running Firebug during a failed request the request shows up in the log, then just sits there without showing it is sending any data, eventually it times out.
My question is, what tools can I use to diagnose this connection problem and start to narrow it down to a specific cause so I can fix it? Its an intermittent problem so a long running tool would probably make more sense, if there is any available.
Thanks for any help.
All of your standard ping and traceroute tools are probably your best bet. I'm not understanding though, where is the site located?
If you open command prompt, run ping -t aspwebsiteurl.domain <- will show if there is packet loss.
From command prompt again, tracert aspwebsiteurl.domain <- will show you what route the packet is taking to get the site. May also show you if there is one particular hop that is giving you the hickup.
Is there a proxy between the office and the datacenter that could be causing issues?
Also you could try Wireshark to try to debug the problem in more detail.
Speed Test - Internet Network Connection Speed may be of some help with some links to test out the connection at the client's office to see how well it works.
Another question is how far away is the client and the datacenter? If one is in New York and the other in Los Angeles then the distance apart may be a factor. Also, have you examined any possible DNS issues?