We are attempting to deploy a SignalR site on a Citrix NetScaler, as opposed to the current deployment on a single server. There are three servers in the farm. If you navigate to any single server, SignalR comes up fine. If you go to the NetScaler address, you get this:
WebSocket connection to
'wss://mysite.com/myapp/signalr/connect?transport=webSockets&clientProtocol=1.5&connectionToken=(token_displayed_here)'
failed: Error during WebSocket handshake: net::ERR_CONNECTION_RESET
After this error, there is about a 10-15 second delay, then it starts working. If I attempt to disable websockets as I have read that Netscalers still have issues with them, the error goes away but the delay remains. I believe the delay is caused by it trying to connect with ServerSentEvents and failing that as well. It appears that only long polling may be working over the NetScaler.
We have checked the NetScaler websocket settings, made sure the servers have the correct machine keys, had a backplane set up (tried Redis and an Oracle Nuget package as that's our typical DB), checked the OWIN versions and web.config settings, all of the stuff that Google told me to do that I could find but still get this error and delay. One thing that I did find is that Netscalers have issues with wss, but haven't been able to find anything about how to account for this. Most of the information found was for people using other load balancing technology.
Is using SignalR (or more specifically, WebSockets or ServerSentEvents) with a NetScaler even doable, and if so what could be causing this problem?
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Am working with wso2esb4.9.0 and having around 160 services which are http and are processed frequently, Initially when the server is started every thing is fine all service request response is up to the mark,
After 10-12 days the ESB server gets hanged does not process any request and no exception are seen in the log file even,They are some request which may be piled up in the server and not allowing new connection to process.
when i do restart of the server all the connections get releases and works for other 10-12 days again.
But doing a restart of the server may not be a good idea to do , where can i find these connections and close them if possible and am i missing any config changes of wso2 esb.
Am trying to find some different connection number using JMX and also what to know if any one face this issue and found the possible solution.
We've got a mirrored SQL server 2012 database setup on Azure VM's - two servers plus a witness, all using client certificates, with SQL logins with the same SID set.
When testing our app from a different VM, everything works as expected when we manually failover the database, there's a one second wait and then it continues to operate quite happily.
If we then do another manual failover, ie moving the principal back to the original server, the app errors and throws a 'no such host in known' error. Recycling the app pool fixes the issue, but this clearly isn't workable in production when one of the servers is updated followed by the other at some later point (both are in an availability set).
The host not known error is somewhat baffling as it was communicating with it happily before the initial failover, and will again after the app pool recycle.
Here's the connection string as it is right now, after a lot of faffing around:
"Data Source=server1,1433;Failover Partner=server2,1433;Initial
Catalog=;MultipleActiveResultSets=True;User Id=user;
Password=password; Network=dbmssocn;Connect Timeout=60; async = true;"
providerName="System.Data.SqlClient"
The app is running on .net 4.5.2, so should be up to date with hotfixes, and we're out of ideas after much Googling with Bing.
I've just solved a problem that I had that looks very similar to your problem. I'd get the host not known error whenever the database switched from the first one listed in the web.config file to the failover one. It was fine switching from the failover to the primary.
The problem that I had was that I set up the database mirroring using server names but my web server did not know the database servers by name. Once I fixed this, I was able to get the failover working smoothly both ways.
This is what I think was happening:
I set up the mirroring using the names SQL1 and SQL2 as the principal and mirror servers
I have their ip addresses in my connection string: 10.1.1.5 and 10.1.1.6
The application tries to get to the first server 10.1.1.5 and succeeds and is then told that the mirror server is SQL2
SQL1 goes down and the database is successfully switched to the mirror server.
The web application attempts to connect, fails and determines that it should try the second server.
It tries to connect to SQL2, which it doesn't know, and fails with the message that the host is unknown.
This answer would only apply to your situation if you actually put ip addresses in your web.config and that server1,1433 and server2,1433 were actually masking place-holders for the ip addresses that you actually used.
I haven't really solved the naming issue though. I just added the two database server names to the HOSTS file which isn't an acceptable situation but does prove my theory on what my problem was.
I am researching a setup just like you have and upon reading this and the response by Steve Kaye, I'm wondering if you have SQL browser running. Take a look at this article for how SQL browser comes into play:
http://blogs.msdn.com/b/spike/archive/2010/12/15/running-a-database-mirror-setup-with-the-sqlbrowser-service-off-may-produce-unexpected-results.aspx
I am trying to build a java application to scrape a website using HTMLUnit. After extracting some data the application encounters following exception -
java.lang.RuntimeException: org.apache.http.conn.HttpHostConnectException: Connection to siteURL refused.
If I run application again, it is able to extract some data again before failing with the same exception. Probably the server see lot of requests from same client IP and refuses connection for a request.
Also, when application encounters this problem, I am able to connect to the site using a browser.
How can I overcome this problem? In web scraping applications how are such problems approached and resolved?
This is how I debug such issues :
Download Fiddler
By default, fiddler listens on port 8888, all you have to do, is configure webClient to use fiddler as proxy & then all requests being sent can be seen (analyzed, modified & re-sent too) in fiddler.
client.getOptions().setProxyConfig(new ProxyConfig("127.0.0.1", 8888));
From what I can say from my previous experience is that the target site blocks after some-time, you can try adding a pause or rotating proxies & user-agents. You can also try clearing cookies.
I have writen a windows service that overwrite Logon and Logoff methods of ISenesLogon2 to check out when logon and logoff occure and then insert the log information into the sql server on server computer.
But it has problem when i turn on the client computer just after the server.
In this situation my service could not insert in sql server.
I think it's because of that the sql server did not load completely before the winservice tried to access to it.
So i want to find a way to check programmatically if the sql server is ready and then try to work with?
Your service cant start until its dependencies remote or otherwise have also started. Checking SQL Server is easy, try and connect to it and retry until you succeed.
Only problem is services have timeouts on startup, you cant sit and repeat this indefinitely.
Things that cannot be reliably started in a reasonable timeframe should not be services or they should fail as soon as possible. Otherwise you will end up with a lot of support requests for your service timing out.
Services are also usually not interactive to the user, so the failure is worse because you cant directly tell the user that your not up unless you do a tray icon.
I'm having a problem with a MVC (1.0) app that I can't figure out at all. There's two versions of the site (live and UAT) hosted on the same server. For each version of the site, the same code is shared by multiple organisations who each have their own database (MSSQL2005) and a separate web site in IIS (7.5) (pointed to the same code).
The UAT site has an update to the code and the database that is waiting to be deployed to the live site.
One of the customers ("customer A") is getting an error "104: Connection reset by peer" when they try to log in to the UAT site. They can see the login page but when they submit their login details the connection seems to be timing out (the requests seem to take ~130s to complete).
Customer A can log in fine to the live site. The other customers don't have a problem logging into the UAT site or the live site. If I try to log in as customer A, using their login details, it all works fine from within our network, and also from outside our network.
Customer A seems to be using squid as a proxy.
I can't think what the problem could be, and I've run out of ideas of things to test. The fact that I can log in as the customer fine and other customers don't have any issues seems to eliminate the code and database as problems.
What other things could I do to try and isolate the problem?
By dumping out the request data I was able to work out that something (I'm guessing the proxy) was removing the form values from the request. This obviously meant the app didn't work properly.
However, it seems whatever was removing the form data was leaving content-length unchanged, which would explain why the client was timing out waiting for more data and the server thought it was finished.
By using https instead of http (which we were going to do anyway), the request tampering seem to have stopped.