Disable IPv6

We had World IPv6 launch day last week, when major websites and ISP turn on IPv6 permanently. I also have a IPv6 enabled for my server, but the problem is it's not working. When I tried to get a file with wget, I got:

Connecting to iweb.dl.sourceforge.net|2607:f748:10:12::5f:2|:80... failed: Connection timed out.

So instead of using "wget", just use "wget -4" to force wget using IPv4. Problem solved? Actually no. When I do apt-get or "gem install", I have no way to tell it to use IPv4. So I just do this to disable IPv6 on my server completely:

echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6

Sorry, da internet, when both you and I are ready, I will turn on IPv6 again.

Find RPM for a certain file

I need to install GHC7.4.1. But the version of GHC that come with Fedora 16 is 7.0.4. So I did a "yum remove ghc" to uninstall it. But GHC (/usr/bin/ghci) was still there. I then found the command for looking up a RPM associated with a certain file is "rpm -q --whatprovides filename_fullpath". So I did:

rpm -q --whatprovides /usr/bin/ghc

, it tells me the RPM name is: "ghc-compiler". I then "yum remove ghc-compiler" to uninstalled GHC 7.0.4 and proceeded to install GHC 7.4.1.

Stop IPsec Policy Agent

My Win Vista laptop's disk activity light kept flashing to no end. Something was killing my disk. I opened "Reliability and Performance Monitor" and found a service called "svchost.exe (LocalSystemNetworkRestricted)" was to blame. After some poking around I found this's not Superfetch, Windows Search, or font Cache. It's "IPsec Policy Agent". I stopped this service, my "Disk % Highest Active Time" dropped from 100% to 0-1%, and stayed here. The disk activity indicator light stopped flashing. I disabled this service. If later I need to do VPN, I will probably have to re-enabled it again. Hope I remember it.