Unable to disable TCP keep alive probing

Hello,
I work with a mobile phone which seems to have problems if a keep alive packet arrives close with a payload packet. Therefore I would like to disable keep alive probing on my Java 1.5 windows XP plattform.
I tried it with:
Socket socket = serverSocket.accept();
socket.setKeepAlive(false);
However the Java application sends keep alive probes anyway. Is this a known bug? Are there some workarounds?
Even if the keep alive is enabled, Java seems to violate RFC recommendations guiding to set an interval of 2 hours. If I sniff with Ethereal I can see keep alive packets in an interval shorter than 2 minutes (sent from the java application socket).
Is this another bug?
Kind regards
Hans-Joerg

(a) Java doesn't send keepalives at all, so it's not 'another bug'. The TCP stack sends them.
(b) TCP may only do so if the application has specifically requested them, which you haven't.
(c) Java doesn't turn TCP keepalive on by default.
(d) TCP may only send a keepalive packet every two hours, unless a global system setting has been changed, which you haven't mentioned.
So, (e) if you're getting them unasked, and more frequently than two hours, either the TCP stack has a major bug, which isn't likely, or they're not keepalive packets, which is orders of magnitude more likely.
The phone shouldn't have any problem with real keepalive packets: they're just acknowledgements quoting a sequence number 1 less than the receiver expects, so the receiver replies with the correct sequence number. This shouldn't cause a competently implemented TCP stack any grief whether in a mobile phone or a supercomputer.
So I would examine your assumption that it's a keepalive packet.

Similar Messages

TCP KEEP ALIVE

Hello we have a problem with TCP/IP keep settings.
We have an apllication that after a while (2 hours) doesnt keep its connection,And after that we are taking of timeouts and disconnection from this application.We saw some threads that there a registery TCP/KEEP ALIVE,we already change this registery but
it doesnt help still.Could it be any other solution?Or advice?

I want to configure it to a lower value so that the connection is not closed by routers/firewalls assuming the connection to be idle.For all TCP clients and servers?
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime 30000 30 seconds is an absurdly low value. Routers and firewalls will typically close connections after an hour, if at all. So setting it to 30 minutes should be adequate. Setting it as low as you have only exposes you to more network problems: if someone has a cable out for 30 seconds you will get disconnected, even if the cable was put back after 31 seconds and even if your application doesn't actually exchange data every 30 seconds. Don't do this.
Is there a standard way in which the keep alive time can be configured on all OS platforms? No.
If not, is this a standard way of changing keep alive time for java applications on windows?The registry keys might differ from version to version. It's a Windows question, not a Java question.
Is it necessary that the machine be restarted on changing keep alive time or is there a specific time by which the new keep alive time would be picked up during run time or on restarting the java application?Another Windows question.
But I would review your requirement. More likely you should be building application pings into the applications that actually need them.

How to add network .keep alive back to firefox... it's missing and my browser is too slow. i need your help i can't work like this

<blockquote>Locking duplicate thread.<br>
Please continue here: [[/questions/954029]]</blockquote>
keep alive missing from about:config settings can it be added back? tell me how and i will

No, you can't add this missing pref back.<br />
Support to disable keep-alive has been removed and keep-alive is always enabled.
See "A Preference to disable HTTP Keep-Alive has been removed":
*https://developer.mozilla.org/en-US/docs/Site_Compatibility_for_Firefox_17
*Bug 770331 – Remove HTTP Keep-Alive disable pref

Keep alive TCP setting for port 3998 to avoid fw timeout?

Hello,
in our new DS6.1 env, replication between the master DS is using port 3998 through several firewalls. If there are no changes to the DB (we are still testing), the connection seems to time out on the firewall and the status of the remote masters in the SMC drops to "stopped" even though they are still running. If one clicks on the DS entry in the SMC, it seems to set up a fresh TCP connection and the status is ok again.
Is there a way to define a keep-alive setting for these connections ?
TIA,
heinz

DS 6.3 has bug 5087249 against it for the missing SO_KEEPALIVE socket option.
This bug was fixed a long time ago in the DS 5.x series which got "unfortunately lost" on the way
to the 6.x release :-(
If you have a valid Sun Support contract you can request a hotfix for this bug 5087249 in
DS 6.3 (or the soon to be released 6.3.1), by raising a support service request.
A similar missing SO_KEEPALIVE socket option bug exists in the DPS 6.3 server,
bug 6782659 is open against this and if you have a valid Sun Support contract you can
request a hotfix for this bug 6782659 in DPS 6.3 (or the soon to be released 6.3.1).
Without a valid support contract, I'm afraid you'll have to wait until the next official patch
release of both these servers (DPS & DS) after the 6.3.1 which does not contain these 2 fixes.
This will most probably be at least one year into the future from present.
The problem with CLOSE_WAITs DPS issue is fixed in the same hotfix for bug 6782659 (which
contains many connection handling bug fixes/enhancement in addition).
Hope this helps.

Disabling Keep Alive

We are using GWT with Glassfish and Sun Web server. We're encountering occassional problems causing the servlet to fail with "Client did not send xxxx bytes" exception.
I read in another post elsewhere that people have solved this problem in Glassfish-Apache configuration with the following settings:
SetEnv force-proxy-request-1.0 1
SetEnv proxy-nokeepalive 1
Can someone tell me what is the equivalent setting in Sun Webserver?
Thanks

Try "set-reverse-proxy-prop"
[http://docs.sun.com/app/docs/doc/820-2204/set-reverse-proxy-prop-1?l=en&a=view|http://docs.sun.com/app/docs/doc/820-2204/set-reverse-proxy-prop-1?l=en&a=view]
* use-keep-alive Indicates whether the HTTP client should attempt to use persistent connections. The default value is true.
* keep-alive-timeout The maximum number of seconds to keep a persistent connection open. The default value is 29.
* always-use-keep-alive Indicates whether the HTTP client can reuse the existing persistent connections for all types of requests. The default value is false, indicating that persistent connections will not be reused for non-GET requests or for requests with a body.
* protocol The HTTP protocol version string. By default, the HTTP client uses either HTTP/1.0 or HTTP/1.1 based on the contents of the HTTP request. In general, you should not use the protocol parameter unless you encounter specific protocol interoperability problems.
...So, probably this will work for you:
set-reverse-proxy-prop use-keep-alive=false protocol="HTTP/1.0"

Keep alive script for HTTPS service with GET method

Hello,
I tried to implement a keep alive to services that support HTPS connections. Ive created a script that opens a tcp connection on port 443 and tries to do a GET of a test web page. This web page only displays OK.
In a resumed form I used the following script commands:
Socket connect host 192.168.136.134 port 443 tcp
Socket send ${SOCKET} GET /teste.template\n\n
Socket waitfor ${SOCKET} 200 2000
Socket disconnect ${SOCKET} graceful
I was unable to receive the expected 200 response and received a message saying string not found, I used the socket inspect command to inspect the sockets internal data buffer and the result was nothing, it seemed empty.
I tried the same operation using a linux machine that has IP connectivity with the Webservers and I was successful.
In the same CSS I have services configured to respond to HTTP sessions. I tried the following script and everything went well
Socket connect host 192.168.136.151 port 80 tcp
Socket send ${SOCKET} HEAD /index.html\n\n
Socket waitfor ${SOCKET} 200 2000
Socket disconnect ${SOCKET} graceful
When I issued the socket inspect command I could in fact see the sockets internal data buffer content.
The CSS is running WebNS 5.0 build 66
Can someone give me a help?
Thanks,
Ricardo Lourenço

Hello,
There is no direct no direct link between TCP and SSL.
So, in spite of having success with the TCP port 443 connection the CSS will not be able to negotiate de security parameters necessary to establish the SSL session.
This was the reason for not having success through the use of the socket commands, as i refered in my original message.
Thanks for your collaboration,
Ricardo Lourenço

Weblogic proxy plugin closes keep-alive connections to clients randomly

In short we have following arhitecture:
clients ---> wl proxy plugin 1 ----> weblogic 1
clients ---> wl proxy plugin 2 ----> weblogic 2
Beacuse of the application/installation specific requirements, we are not using failover, one wl proxy always forwards requests to one weblogic (simple configuration).
Application is TR-069 protocol based (SOAP over HTTP) so it very much relays on persistence TCP connections (Connection: keep-alive). This TCP persistence has to work correctly in order that TR-069 messages are exchanged in required order, otherwise we have a error on application layer.
Here and there we've noticed applications errors which suggest that we have some problems in TCP connection between the client and the weblogic server. After sniffing, we've noticed that weblogic proxy plugin (Apache) randomly, or because of some other reason we do not know, decides to close TCP connection to client, even app on weblogic did not request so ???
As a result, client opens new connection to the server with new TR-069 session and it gets bounced beacuse it allready has one open on weblogic server.
We've sniffed, traced everything we could, we were searching for patterns in time, etc... but we can not find the reason why proxy plugin decides to close the connection to the client (not to the weblogic server).
Trace (replaced sensitive information):
Thu Apr 29 15:05:50 2010 <958012725463463784> URL::parseHeaders: CompleteStatusLine set to [HTTP/1.1 200 OK]
Thu Apr 29 15:05:50 2010 <958012725463463784> URL::parseHeaders: StatusLine set to [200 OK]
Thu Apr 29 15:05:50 2010 <958012725463463784> parsed all headers OK
Thu Apr 29 15:05:50 2010 <958012725463463784> sendResponse() : r->status = '200'
Thu Apr 29 15:05:50 2010 <958012725463463784> canRecycle: conn=1 status=200 isKA=1 clen=545 isCTE=0
Thu Apr 29 15:05:50 2010 <958012725463463784> closeConn: pooling for '$IP$/$PORT$'
Thu Apr 29 15:05:50 2010 <958012725463463784> request [$URL$] processed successfully..................
!!!! Now it closes the TCP connection and inserts "Connection: close" HTTP header !!!
WL proxy plugin conf params are:
WebLogicCluster $IP$:$PORT$
DynamicServerList OFF
KeepAliveTimeout 90
MaxKeepAliveRequests 0
KeepAliveSecs 55
Apache worker configuration is:
<IfModule mpm_worker_module>
PidFile var/run/httpd-worker.pid
LockFile var/run/accept-worker.lock
StartServers 2
MinSpareThreads 25
MaxSpareThreads 75
ThreadLimit 200
ThreadsPerChild 200
MaxClients 2000
MaxRequestsPerChild 0
AcceptMutex pthread
</IfModule>
Why weblogic proxy plugin ignores Keep-alive directive and decides to close connection to the client by itself?
Any help?

If a WebLogic Server instance listed in either the WebLogicCluster parameter or a dynamic cluster list returned from WebLogic Server fails, the failed server is marked as "bad" and the plug-in attempts to connect to the next server in the list.
MaxSkipTime sets the amount of time after which the plug-in will retry the server marked as "bad." The plug-in attempts to connect to a new server in the list each time a unique request is received (that is, a request without a cookie).
Note: The MaxSkips parameter has been deprecated as the MaxSkipTime parameter.
See also here: http://download-llnw.oracle.com/docs/cd/E13222_01/wls/docs81/plugins/plugin_params.html
You said the problem arises under significant load. Maybe, it is wise to tune the number file descriptor's on your operating system. HTTP connections are nothing more than TCP sockets on the operating system. All modern operating systems treat sockets as a specialized form of file access and use data structures called file descriptors to track open sockets and files for an operating system process. To control resource usage for processes on the machine, the operating system restricts the number of open file descriptors per process. You should be aware that all TCP connections that have been gracefully closed by an application will go into what is known as the TIME_WAIT state before being discarded by the operating system.
On most unix systems you can use netstat -a | grep TIME_WAIT | wc -l to detemine the number of socket in time_wait state. You have to check with your system adminstrator how to tune the tcp_time_wait_interval. On solaris you can use: /usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000

Http keep-alive with SOAP webservices

Just had an interesting experience with a web service setup behind UAG...under low load conditions all SOAP responses were coming across with no issue...once a high load was introduced by the client app the behavior changed where an initial request was
processed and subsequent requests were rejected by UAG with a Bad Parameter : Length message...but high load (relatively) on a web browser ran without issue...the client app had to wait ~100 seconds before the next request would process correctly...browser
works - app has problems...turns out it was the keep-alive "default" settings on both the client app server, as well as my web service in IIS...so -apparently UAG thought the 2nd (and subsequent < 100 seconds) were a parameter of the first request...and
was way too long and got rejected...I unchecked the keep-alive enabled box on the http response header (set common headers) and all is fine now! Apparently the browsers were closing the connection with each page load and the service responded appropriately
- so it looked like all was well. Using SOAP UI revealed the error...but it also had it's connection set to keep-alive...once that was disabled in SOAP UI all requests ran correctly...that's when I poked around and found that response header setting.

ejp wrote:
and also an incorrect implementation of the timeout period. This code will still wait forever if no data arrives.You're right... actually I didn't mean to put that while loop there! What I meant was simply
if (!reader.ready())
wait(keepAliveTimeout);
if (!reader.ready())
break mainLoop;
// If we get here there is a new request to read...and I agree that it's ugly, that's why I'm asking you guys for help!
setSoTimeout() is of course a way to go... didn't think of that although I have kind of already added it to my code but with a different timeout. Thanks!
Last question then is:
does reader.readLine() block like reader.read(), or do I have to use the latter?
I would test for myself I could, but at the moment I can't...

Question about Keep Alive feature in Forte 3.

Does anyone use Keep Alive feature under Forte 3.0F.2 environment.
I got trouble and encounters the following problem in the service objects
daily:
INFORMATION: An abnormal disconnect from partition
(CFFE2500-85B0-11D1-B37F-E2F7F3F1AA77:0xec254) was received. Since there
are
no method invocations outstanding to this partition, no notification could
be
given of this disconnect (by indicating a method invocation failed).
Therefore, the information associated with this disconnect is being
reported
to the log.
Class: qqsp_DistAccessException
Error #: [601, 119]
INFORMATION: The connection to the partner was terminated by the
Communication Manager for the reasons below.
Class: qqsp_DistAccessException
Detected at: qqdo_PartitionMgr::StopLocation at 1
Error Time: Fri Nov 26 17:45:39
SYSTEM ERROR: Failed to establish connection: OS Error 61: Connection
refused
Class: qqsp_DistAccessException
Detected at: qqcm_HoseFSM::SetError at 5
Error Time: Fri Nov 26 17:45:39
SYSTEM ERROR: hose 15 STATE_CONNECTING (EXT_RECEIVED) from
qqcm_HoseFSM::IssueConnect (after EstablishConnection)
Class: qqsp_ErrorDescriptor
Detected at: qqcm_HoseFSM::SetError at 1
Error Time: Fri Nov 26 17:45:39
It seems that Keep Alive sometimes disconnects the connection between the
service objects and the environmental manager.
So that any further connection request from the client encounters the
abnormal exception.
Forte seems not to recommend to use this feature in the Forte Relase note
3.0J1.
She states that "Sites that chooses to test KeepAlives should report all
problems to Technical Support ( and let
Technical Support know that you have enabled this capability)"
Should I disable Keep Alive feature under Forte 3.0F2 environment?
Rgds
Tom

Hey Marco,
I can`t find a view that is named like "APEX_APPLICATION_PAGE_IR%". Is it not available on the evaluation instance.
I don`t want to use the build-in CSV download, becaus I want to export thousands of data sets. I got this already to work with APEX 3.0 and I get the sql from the application views. The procedure which creates the file runs a few hours and after that it is inserted into a table from which the user can download the file. In the procedure there happens a few other things, which are very import, so I have to create my custom solution.
And for that I thought it would be very very very cool if I can get the sql behind the interactive report with the filters ant those things.
Don`t you think that would be possible? I guess the APEX create a SQL although, or am I wrong?
Thank you,
Tim

Weblogic shutting down keep-alive socket improperly?

We were sometimes experiencing strange IE behaviour when surfing on webapps on our Weblogic application servers. After investigation we found that IE has a bug in its resend behaviour, so when resending a POST request it sends the headers (including Content-Length) but forgets the form-data. This causes the server to time out waiting for the data. (Note: We are using Win2K and IE6 SP1 on the clients.)
The IE resend is triggered on a default installation when 31-59 seconds have passed since the last request.
This is because IE will try to reuse a socket that has been told to keep-alive until it has been idle for 60 seconds but WLS will by default close kept-alive sockets when they have been idle for 30 seconds. So in the range 31-59 seconds IE will consider the socket alive but WLS has closed it.
The resend bug is really an IE bug and doesn't concern WLS, but then I saw that IE would function correctly with an Apache server with a default keep-alive timeout of 15 seconds.
Using Ethereal I could get the information depicted in the tables below:
Weblogic with keep-alive timeout 30 secs
old socket
Time 00 : User navigates : IE POST request -> WLS, WLS HTML -> IE
Time 30 : Socket times out : (no network traffic)
Time 45 : User navigates : IE POST request -> WLS, WLS TCP_FIN -> IE
new socket
Time 45 : : IE resends POST request without form-data
Apache with keep-alive timeout 15 secs
old socket
Time 00 : User navigates : IE POST request -> Apache, Apache HTML -> IE
Time 15 : Socket times out : Apache TCP_FIN -> WLS
new socket
Time 45 : User navigates : IE POST request -> Apache, Apache HTML -> IE
To summarize, IE handles Apache well as Apache sends a TCP FIN telegram (to close the connection) as soon as the kept-alive socket times out.
Therefore IE never tries to reuse the socket but instead starts on a fresh one on the next navigation and a resend is never necessary.
Weblogic, on the other hand, doesn't send the TCP FIN (connection close) telegram until IE actually tries to use the connection even though it timed out 15 seconds earlier. In this case IE needs to resend the POST request and this is when the form-data is forgotten.
So, my question now is if WLS behaviour could be caused by not shutting down kept-alive sockets properly at keep-alive timeout? Or why are there no TCP FIN telegrams sent at timeout?
Mike Wilson

After doing some more investigation I have found that the "silent" shutdown of keep-alive sockets is only seen on the Linux version. The Windows version of Weblogic 8 behaves correctly, like Apache on Linux, but Weblogic on Linux does not...
Anyone can confirm if this is to be considered a bug?

HP Pavilion g6 Notebook unable to disable Touchpad or access Synaptic to configure it

Recently, I have been unable to disable my Synaptic Touchpad on my HP Pavilion g6 Notebook and, me being a gamer, it is quite annoying fore I always end up moving the Touchpad with my wrist which will, in turn, move my Cursor.
I have done research on this problem and all the answers I have found, I tried and they proceeded to fail. I am quite infuriated and do wish someone knew what was going on and will help me.

Dear Customer,
Welcome and Thank you for posting your query on HP Support Forum
It looks like you are facing difficulties with the Touchpad of your Notebook
We will surely assist you with this
Steps to drain the Static charge and loading default BIOS settings to resolve the issue
Step 01. Turn OFF the Notebook
Step 02. Un-plug the Power/AC Adapter and also remove the Battery too
Step 03. Press and Hold the Power Button of the Notebook for a full minute
Step 04. Now let's re-insert the battery back in and plug back the Power/AC Adapter
Step 05. Start the Notebook and keep tapping F10 Key during the startup to access the BIOS
Step 06. Once you get to the BIOS, Please press F5 Key to load setup defaults for the BIOS
Step 07. Now let's press Esc/Escape Key. Save Changes and Exit - Yes
Step 08. Now please wait till the Unit loads the Windows Operating system
Now please re-install the touchpad drivers from HP Website in order to resolve the issue
Click on the below shown link to find the steps involved in disabling the Touchpad
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c03922412
Hope this helps, for any further queries reply to the post and feel free to join us again
**Click the KUDOS star on left to say Thanks**
Make it easier for other people to find solutions by marking a Reply 'Accept as Solution' if it solves your problem.
Thank You,
K N R K
Although I am an HP employee, I am speaking for myself and not for HP

"Keep Alive" parameter for listener?

Hi all,
we have following problem:
From time to time the client (oracle forms 6i patch 18) gets the error message ORA-03114. Te solution is only to kill forms application and start it again.
This hangs probably on the network breaks in the communication (over VPN) with the database.
Is there any parameter for listener like "Keep alive" or else, which can rebuild the connection once it lost?
Best regards

Paste this into the SQLNET.ORA on the application server or the server that is making the SQL calls to the database.
Trace_level_client=16
Trace_directory_client=<path_to_the_trace_directory> # use the full path to the trace directory
Trace_unique_client=on
Trace_timestamp_client=on
Then review the trace or you can try the keep alive in windows
Use the standard TCP KeepAlive on Windows
1. Open the registry under:
HKEY_LOCAL_MACHINE: SYSTEM: CurrentControlSet: Services: Tcpip:
Parameters
2. Add KeepAliveTime : REG_DWORD to the registry
3. Set the value to a reasonable timeout.(decimal and NOT Hex) Like 480000 equals 8 minutes or 120000 equals 2 minutes etc etc.
- Save this
- Reboot

Keep Alive SMTP connection

Hi,
Is there any way to keep alive a SMTP connection forever using JavaMail? I know being a TCP connection, the connection will be broken if no data is exchanged for specific time. What if NOOP command is send to SMTP server as a heart beat. Can anybody suggest how this can be accomplished using JavaMail?
Thanks,
Atul

You can call the isConnected method, but your server isn't going to like you if you
keep a connection open even though you're not using it.

GF3.0 - Enabling HTTP keep-alive?

In GF 2.0, there's a handy-dandy tab on the HTTP Listener configs for enabling and configuring HTTP keep-alives. In GF 3.0, there is not.
I've been combing various sites and blogs and docs and have been unable to find any information on enabling HTTP keep-alives. Some data I've found seems to suggest that raising the Max Connections and Timeout values for the listener to values greater than 1 implicitly enables keep-alives, but if I test the server with AB it shows zero keep-alive requests.
Any help that anyone could provide would be greatly appreciated.

[glassfish@appserver ~]$ asadmin get -m \*keep-alive.\*count
Enter admin user name> admin
Enter admin password for user "admin">
Command get executed successfully.
[glassfish@appserver ~]$ asadmin get "server\*keep-alive.\*"
Enter admin user name> admin
Enter admin password for user "admin">
com.sun.enterprise.admin.cli.CommandException: remote failure: Dotted name path server\*keep-alive.\* not found.
Command get failed.

HFM Web Sever Configuration--Keep Alive and Session Time Out Optimal Config

We recently implemented an HFM 9.3.1 environment. We are using Windows 2003 Enterprise SP2 servers with IIS6. We have two HFM Web servers connecting to an application cluster with two application servers in the cluster. We were getting some errors when trying to unlock HFM cells in Workspace, but we were able to perform the functions fine on the application using the WIN32 client.
I opened a ticket with support and they recommended modifying the subcontext.properties file located in %HYPERION_HOME%\deployments\WebLogic9\servers\Workspace\webapps\workspace\conf. They recommended changing the following settings:
#KeepAliveInterval=30
#SessionTimeout=60
From what I understand, these settings are for the communication between the HFM Web Servers and the application cluster servers. I'm wondering how changing these settings may affect our environment. Are there negative effects and/or trade-offs for changing these settings? Is there a recommended threshold or maximum value?

Hi Dinesh,
This cannot be achieved without development enhancements to some standard SAP framework component, to introduce a "keep-alive" concept. If you are using a CMS for CTI or email integration, you need to ensure it supports keeping the communications session alive also.
Sincerely,
Glenn
Glenn Abel
Covington Creative
www.covingtoncreative.com

Unable to disable TCP keep alive probing

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