TCPv4 Connection Failures and Active - tcp

Good evening everyone,
I've a question, we have some servers, by customers, where the TCPv4 Connection Failures and Active are increasing an lot
How can i troubleshoot from where it's coming ?
It looks that after some time like this, when we have too much connection, the machine crashes. We have to restart it
Is it coming from software, or could be coming from Hardware (network card) ? Driver to update ?
Thanks for help, i'm a little confused about this i don't know where and how look to fix this problem.
We don't have this problem by every servers... i don't know if it's software or hardware.

Related

Network stack crashed?

Our software includes a module to stream live video data to multiple clients. Most of time it works fine, but in some cases it seems to have caused some malfunction of windows network.
When it happens, the LAN connection status in network connections still says "connected", and the IP address is normal. But I cannot ping any other device in the network. The only way to fix it is to disable and then re-enable the network connection.
This problem seems to be OS-independent, it has happened on XP, Vista and Win7 machines.
Has anyone experienced anything similar? Did my application crashed the network stack? or is it something else?
More likely a fault with the networking switch unless you have a really bad NIC.
Cheapest route is to first replace the NIC, but ideally you should be able to reproduce the fault in a test harness so try with a direct crossover cable between two hosts first to rule out the networking infrastructure being at fault.
∴ Server Fault could be a better place to ask the question.

How to troubleshoot networking problems

I am seeing a problem with few IP Cameras as I am loosing connections with the cameras from the server. The connection loss happens after running for few months. I don't loose the connection with all the cameras.
Please provide pointers on how to trouble shoot this problem.
Thanks,
Sunil
Wireshark, to analyse what happens when you lose the connection

prove network is truly unavailable

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.

ASP.NET AJAX application extremely slow over VPN

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.

How to find where a connection is failing

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?

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