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?
Related
I am working for a company that is providing File-Share-Software for all sorts of Protocols such as FTP, SFTP, FTPS and so on. One of our customers is facing an issue with Key-Auth and spontaneously login-problems.
Going trough the code I am pretty certain that the server collapses with too many requests at the same time. What I need right now is a simple tool to test a situation just like this. I need a simple SFTP-Fuzzer or Stresser, sending invalid or broken Auth-Attempts to the SFTP-Server.
I am not a developer but a technician and instead of writing something myself (which would take forever) I would love to have a simple script or toolset to go...if there is one.
Ok, found one faster than I thought.
Steps:
Download Kali Linux (or any Distro that contains Metasploit)
Fire up Kali Linux and put it in the same subnet as your SFTP-Server
Start Metasploit and use the SSH-Fuzzer /auxiliary/fuzzer/ssh/ssh_version_2
Set RHOST and RPORT to the relevant IP and port your server is listening to
Exploit and see what will happen
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'm having a lot of trouble with an EC2 instance and I can't figure out what's going on. We're using it as a web server and it seems to work fine for single connection stuff - loading a simple page, RDP connection, ping etc. But as soon as a single client computer has more than one connection active with the server (a good example is if I try to browse the web site while I'm also logged into the server via RDP) the whole connection becomes incredibly unstable.
The biggest most annoying consequence of this is that the ASP.NET site that we're running consistently fails to load some pages since those pages use more than one connection. This wasn't a problem up until a few days ago when we were forced to migrate to different hardware because our hardware was apparently being retired by Amazon. Ever since then it's been tricky like this. Is it possible that there's a kink in Amazon's network and that it could potentially be resolved by stopping and starting the instance (and thus getting a different server?)
It turns out the problem was an underlying issue on Amazon's end. They investigated the issue and found a problem that they're correcting. I hope I haven't wasted too much StackOverflow brainpower with this dead-end of a question!
I have an old school foxpro web app that I am trying to help limp along while I rewrite the system. Every day, multiple times, I get this following error message: The specified network name is no longer available.
Does anyone have any suggestions how to troubleshoot this? Perhaps, prove to my IT guys that there really is a network issue. I have theories, but I have no idea how to prove anything, it always comes back to foxpro sucks rewrite it now.
I'll take any help, tools, and will answer any questions that may clarify this for you.
thanks
We have a very large multi-user VFP application on hundreds of sites. Occasionally you get this sort of problem. It is almost always down to environmental issues.
Had one just recently where a client had two machines continually crashing out of the VFP application. Network IT guys swearing up and down that it's not their problem. But what's this in the System Log of both machines? Why, it's the Broadcom NIC reporting a network link loss detected at the same times the application crashed.
Check if the client and server NICs in your situation can report this.
You could consider writing a small program that pings the network resource periodically. You might just look for a file and if the network is failing and the program cannot find the file email the folks in charge of the network and yourself. This would be an independent app, and best if not written in FoxPro so you can independently prove it is not the application or the language/tool it was written in.
I have seen this when networks have bad wiring, a bad port on the switch/hub, a failing NIC in the mix, and sometimes when the network is just flooded with requests from workstations.
You also did not mention if this was a wireless connection. I am hoping not, but I have seen wireless (especially slower wireless) hubs fail with respect to the network overload and slow and unreliable performance. Especially compared to a wired network.
Rick Schummer
In addition to the comments about IP address, is the setting on the network controller to be energy efficient? and thus turn itself off when not actively in use.
I have a ASP.NET AJAX intranet application that has been running for a few months. It runs reasonably fast on the LAN.
However when going over a VPN it slows down dramatically. Even taking line speed into account its takes like 60 seconds to change a page. I eventually got a vmware up and running to test the VPN speed, so the connection is super fast, but it still takes the same amount of time. I can even remote desktop over the VPN to the VMware and its perfect.
This makes me think that its has nothing to do with line speed. FYI I am using Hamachi.
I have tried other VPN software and it gives the same results.
I am really stuck... any help would be much appreciated!
I found the problem was due to trying to do a dns lookup in the code. Changed to just the IP and now working!!!
Try to add system counters for "Byte per second" and other similar parameters of you network. This helps you to figure out the bottleneck of you system.