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My guess is that ipsysctl is short for something like (TCP/)IP System Control, an interface to the TCP/IP functions built into the Linux kernel.

There are a large number of setting that can be tweaked — I suspect that if I really understood them all, I could do something to minimize the occurrences of "Timeout on Server" I get while using twiki.org.

This page contains some notes I collected. I have not (so far) solved the timeout problem, tweaking the ECN (Error Congestion Notification) parameters seemed to help somewhat, but not consistently, but prevented some pages from loading at all, so I left ECN disabled.




Links collected relevant to problem with "server timed out", especially on twiki.org. I have a theory that some single or combination or variation of timeouts in the "ipsysctl" (IP System Control??) thingie leads to the timeout message, but I don't know which.

Methods of checking / setting the variables include:

Using sysctl is recommended over /proc, especially in scripts on the basis that it is easier to read, and all values can be read from a configuration file. Note that:

  • the separator in sysctl is . vs / in proc
  • sysctl might not be installed by default in all Linux systems
  • "certain variables" ... "should not be turned on before a specific time in bootup. For example, it may be a very bad idea to turn on ip_forward before we have all the firewall rules and routes up and running", which suggests that you may want to turn on some single variables sometime after a (not quite) complete configuration file is loaded.
  • "It is unfortunately impossible to block read access to the /proc filesystem as of writing this. The problem is that all read/write permissions are hardcoded within the /proc filesystem itself, and because of this, it is impossible to change the settings manually. If you really really need to change these settings, you can do it for the whole system from within the linux/fs/proc directory, which contains the source code for the Linux /proc filesystem."

All quotes above (unless otherwise noted) are from:


=sysctl -a  | less=
list all variables (do it, it's educational) (-A (future?) for a table)

=sysctl net.ipv4.tcp_sack=
show a specific variable

=sysctl -w net.ipv4.tcp_sack=0=
set a variable

=sysctl -p=
run the default configuration file (/etc/sysctl.conf)

=sysctl -p /etc/testsysctl.conf=
run a specific configuration file

proc filesystem

"All you need to use this method of reading and setting variables is the cat and echo commands as well as a standard shell such as bash. It is highly unlikely that you do not have any of these since all distributions carry these and should be more or less impossible to not install with the installation process."

cd /proc/sys/net/ipv4=
the directory where all ip / tcp variables exist — use =ls to view them


=cat ip_forward=
view a specific variable

=echo "1" > ip_forward=
set a specific variable




See Resource Recommendations. Feel free to add additional resources to these lists, but please follow the guidelines on ResourceRecommendations including Guidelines_for_Rating_Resources.


Executive Summary:

Survey shows 8.3% of websites unreachable from an ECN capable client. Notable unreachable sites:

www.amazon.com, www.ibm.com, www.sun.com, www.apple.com, www.intel.com, www.disney.com, www.espn.com, www.zdnet.com, www.ups.com, www.visa.com, abc.com, cbs.com, fox.com, sharkyextreme.com, www.linuxtoday.com, www.linuxstart.com, www.linuxplanet.com, www.linuxnewbie.org, www.linux-usb.org

Firewalls are improperly rejecting connections, if they aren't fixed, there will be lots of complaining when the linux 2.4 kernel gets widespread deployment.

  • [[http://lists.freeswan.org/pipermail/users/2001-September/003264.html][[Users] Internet for IPSec tunnel completely behind gateway]]; ; ; — and this

  • Squid: System-Dependent Weirdnesses: Solaris: TCP incompatibility?; ; ; — this too, although it might only apply to Solaris


  • () RandyKramer - 05 Oct 2003
  • If you edit this page: add your name here; move this to the next line; and if you've used a comment marker (your initials in parenthesis), include it before your WikiName.

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Topic revision: r1 - 2003-10-05 - RandyKramer
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