Since CentOS 6.x is an old distro it lacks newer GCC and thus you can’t use things like stack protector and some of the PAX security stuff
What you can do however, is to install the SCL repo and from there the devtoolset-4:
# yum install centos-release-scl.noarch centos-release-scl-rh.noarch
# yum install devtoolset-4 devtoolset-4-gcc-plugin-devel.x86_64
The above will install gcc [...]
After yum or apt-get upgrade you are left with services that need to be restarted in order to start using the new libraries you have just upgraded.
Sometimes you know what to restart but if you haven’t done upgrade in a while it is highly possible that you can miss a service.
The following simple two liner [...]
Yesterday I had a very interesting conversation about congestion control and how it affects long lived connections.
So I decided to do a very simple comparison. I created a 100MB file(dd if=/dev/zero of=test-file bs=1M count=100).
Scalable:
test-file 100%[==============================================>] 100.00M 5.13MB/s in 23s
2016-02-28 19:40:55 (4.35 MB/s) - ‘test-file’ saved [104857600/104857600]
Illinois:
test-file 100%[==============================================>] 100.00M 4.20MB/s in 24s
2016-02-28 19:21:57 (4.13 [...]
I finally decided to request full BGP tables from all of my ISPs, so I can easily change the preferred path to certain destinations.
However this meant that now I have to monitor both the state of the BGP sessions, but also the amount of routes that I receive from my neighbors.
Before my days with full [...]
Since I’m a long user of Xchat I decided to upgrade it and found that it does not compile with the recent glib library.
The problem is that the new versions of the glib library introduced one limitation for includes. Now you only have to include glib.h and every more specific inclusion breaks the builds.
Even thou [...]
Very often I login on machines with older mii-tool that reports 1Gbit/s cards as if they are connected on 100Mbit/s. This is normal as mii-tool is depricated. But a lot of old timers like me are used to its output. So I wrote a very simple awk script which can convert the ethtool output to [...]
I had to build a mail server for one client. So I decided to use postfix + dovecot as a combination for the setup.
After a week of usage, my client called and asked for per user quotas. Since the setup is with virtual users this required some changes. So here I’ll try to outline what [...]
One of the problems when you are migrating a server is actually migrating the traffic from the old IPs to the new IPs.
Since we were doing that fairly often for some of our server I have used one very common trick, which was to use DNAT + SNAT to move the traffic from the old [...]
Today I had to install MySQL Proxy on one of our servers.
What I found was that the current stable version 0.7.2 requires more resent version of Glib2 then what comes with CentOS 5.4.
So here is what I did in order to build it with a different version of glib2 then the default installation:
LUA: download & [...]
I started to use syscalls in Perl scripts a long time ago. One of the main issues I face every time I install a script on a new machine is creating Perl header files from the C headers.
It is supposed to be done very easy:
# cd /usr/include
# h2ph *.h
# h2ph */*.h
With this we should have [...]
