Recently, we faced a problem where emails generated from our application were not showing up in AOL inbox(es).
We have recently switched to a new machine & I suspected that for new machine mx-records are not set correctly from where I am trying to send the email.
We didn’t wanted to change our mx-records as we feared [...]
I was trying to download some 150-200 zip files from a http URL by finding each file & clicking on it to download. I soon realized how boring it is using standard download support in browsers.
This is something I am supposed to do periodically
I know that there are some browser extensions available that could do [...]
set this var before gem install command
export CXX=g++
I tried this before mod_rails launched.
Pushing my command log for reference.
This setup uses rubyworks, details can be found here http://studios.thoughtworks.com/rubyworks
I tried this on a redhat machine. The setup seems to be working perfectly fine.
clear
2 ruby
3 yum install ruby
4 wget http://rubyworks.rubyforge.org/RubyWorks.i386.repo
5 sudo cp RubyWorks.i386.repo /etc/yum.repos.d/
6 uname -A
7 uname -a
8 [...]
Well this happens when there are too many files to process:
Best way in this case is to do batch processing:
Sample command:
find . -name ‘ruby_sess.*’ -print0 | xargs -0 rm
Assumption:
- eth0 is the external interface (Connected to internet)
- eth1 is the internal interface (local network) (Fixed IP)
Edit /etc/sysctl.conf to enable ip forwarding permanently.
net.ipv4.ip_forward = 1
Edit /etc/sysconfig/iptables-config and make following changes:
IPTABLES_MODULES=”ip_conntrack_netbios_ns ip_conntrack ip_conntrack_ftp ip_conntrack_irc iptable_nat ip_nat_ftp ip_nat_irc”
IPTABLES_SAVE_ON_STOP=”yes”
IPTABLES_SAVE_ON_RESTART=”yes”
# To clear out any existing rules and set default policy,
# run following commands on command prompt
iptables -P INPUT [...]
RPM packages have a file of names like foo-1.0-2.i386.rpm, which include the
package name (foo), version (1.0), release (2), and architecture (i386).
To display package information before installing the program, use the command:
# rpm -qpi foo-2.3-8.i386.rpm
To install a RPM package, use the command:
# rpm -ivh foo-1.0-2.i386.rpm
To upgrade a RPM package, use the command:
# rpm [...]
Linux has a special command (linux single) also known as ‘single-user mode’, which can be
entered at the boot prompt during startup of the system. The single-user mode is generally used
for system maintenance. You can boot Linux in single-user mode by typing at the LILO boot
prompt the following command:
LILO: linux single
This will place the system in [...]
Configure the /etc/exports file with the most restrictive access possible. This means not using wildcards, not allowing root
write access, and mounting read-only wherever possible.
Edit the exports file (vi /etc/exports) and add:
As an example:
/dir/to/export host1.mydomain.com(ro,root_squash)
/dir/to/export host2.mydomain.com(ro,root_squash)
Where /dir/to/export is the directory you want to export, host1.mydomain.com is the machine allowed to log in this directory, the [...]
- Mounting boot partition read only, increases security of kernel. This how you do it in /etc/fstab
LABEL=/boot /boot ext2 defaults,ro 1 2
And reload changes
# mount /boot -oremount
And yes, make it writable when you are planning kernel upgrade. Otherwise new kernel wont be able to enter
Other security options in the fstab file are:
defaults [...]