These instructions should work fine on any CentOS [...]]]> Here is some advice I found useful when setting up my RPM build environment, and building a basic RPM.  The main source I used, to save reading my book again or the man pages, was Linc Fessenden’s blog and some of Linc’s blog is repeated here for completeness. Thanks Linc!

These instructions should work fine on any CentOS / RHEL / Fedora system.

First off, we need the rpm-build package to be installed. Check and install if needed.
yum install rpm-build

Login to the system as your user account, then make the following directories:


mkdir -p ~/rpm
mkdir -p ~/rpm/BUILD
mkdir -p ~/rpm/RPMS
mkdir -p ~/rpm/SOURCES
mkdir -p ~/rpm/SPECS
mkdir -p ~/rpm/SRPMS
mkdir -p ~/rpm/tmp


And create an ~/.rpmmacros file with the following in it:


%packager Your Name
%_topdir /home/YOUR USERNAME/rpm
%_tmppath /home/YOUR USERNAME/rpm/tmp


Now you need to create a package source code ditectory in the ~/rpm/SOURCES directory. You should name it package name – major revision number. Eg: ~/rpm/SOURCES/robspackage-1. In that directory place all the files that you wish to package in the RPM. I have put “script.sh” in mine.

Once that is done, make a tarball of that directory in the ~/rpm/SOURCES directory named programname-revision.tar.gz. Eg:

cd ~/rpm/SOURCES
tar -czvf rob-1.tar.gz rob-1/


In the ~/rpm/SPECS directory, create a packagename.spec file for your package.
Eg: rob.spec:

Summary: My first rpm package
Name: rob
Version: 1
Release: 1
Source0: rob-1.tar.gz
License: GPL
Group: CustomGroup
BuildArch: noarch
BuildRoot: %{_tmppath}/%{name}-buildroot
%description
Relevant package description
%prep
%setup -q
%build
%install
install -m 0755 -d $RPM_BUILD_ROOT/opt/rob
install -m 0755 script.sh $RPM_BUILD_ROOT/opt/rob/script.sh
%clean
rm -rf $RPM_BUILD_ROOT
%post
echo ” ”
echo “This will display after rpm installs the package!”
%files
%dir /opt/rob
/opt/rob/script.sh
%changelog
* Wed Feb 24 2010 Rob Jervis
- added something or fixed a bug

* Tue Feb 23 2010 Rob Jervis
- First RPM package of the rob application for EL5

Direct Quote from Linc:
“The install lines tell rpm what to install where and with what permissions. You also have to do any directory creation there as well (the one with the -d in the line).”

“The things after %file are similar in that this tells rpm’s database which files are attached to this package. The %dir signifies a new directory, otherwise the files are listed with their complete paths.”

Now you need to create the package, go to ~/rpm and do “rpmbuild -ba SPECS/rob.spec”.
If your package builds ok, it will end up in the RPMS directory, in this case: ~/rpm/RPMS/noarch/rob-1-1.noarch.rpm.

If it fails to build, first check your spec file carefully. Enjoy!

I thought I would share it, place in “/etc/init.d/dnetc”. It should work fine on current releases of Fedora, RHEL and CentOS. Its designed for the sysadmin to configure dnetc for that [...]]]> This week I was looking into init scripts again, its been a while… Anyhow, I remembered that I had written one for distributed.net’s client app.

I thought I would share it, place in “/etc/init.d/dnetc”. It should work fine on current releases of Fedora, RHEL and CentOS. Its designed for the sysadmin to configure dnetc for that system and then manage its start up and shutdown. (Not a script for end users to be using. )

You will need to change the application path to be the directory you have extracted the into.


#!/bin/bash
#
# dnetc This shell script takes care of starting and stopping distributed.net client
#
# chkconfig: 345 90 12
# description: distributed.net client program, a \
# distributed computing project. The program \
# uses only the computers idle time.
# processname: dnetc

# config: /etc/dnetc/dnetc.ini
# pidfile: /var/run/dnetc.pid

# Get function from functions library
. /etc/init.d/functions

start() {
echo -n “Starting DNET client: ”
/custom/dnetc/dnetc -quiet
touch /var/lock/subsys/dnetc
success $”DNET client startup”
echo
}

stop() {
echo -n “Stopping DNET client: ”
killproc dnetc
rm -f /var/lock/subsys/dnetc
echo
}

# —————————————————————–
case “$1″ in
start)
start
;;
stop)
stop
;;
status)
status dnetc
;;
restart|reload|condrestart)
stop
start
;;
*)
echo $”Usage: $0 {start|stop|restart|reload|status}”
exit 1
esac

exit 0

This script could do with some more work, I did put it together quickly, but this page helped me get it going and its worth looking at if you want to write a System V init script of your own.

I started doing a bit of research into [...]]]> I have a web page that lists servers I need to connect to. This page has several hyper links for each server to key webpages on that host. I wanted to be able to connect using ssh too, at the click of a link. (eg: ssh://myserver.example.com and ssh://user@myserver.example.com)

I started doing a bit of research into this and have been able to set it up!

On Fedora 10:
1. Open Firefox and go to: about:config.
2. Right Click > New > Boolean > Enter the following name “network.protocol-handler.expose.ssh” and then “true”
3. Right Click > New > Boolean > Enter the following name “network.protocol-handler.external.ssh” and then “true”
4. Right Click > New > Boolean > Enter the following name “network.protocol-handler.warn-external.ssh” and then “false”
5. Right Click > New > String > Enter the following name “network.protocol-handler.app.ssh” and then “firefox-ssh.sh”
6. Close Firefox
7. Create a script here (/usr/local/bin/firefox-ssh.sh) with the following in it:

#!/bin/bash
gnome-terminal -e “ssh `echo $1 | sed -e “s/ssh:\/\///”`”
8. Run chmod +x /usr/local/bin/firefox-ssh.sh
9. Open Firefox and go to a link like ssh://myserver.example.com

First off I hope to get involved in more FOSS advocacy projects, there are a few about which I hope I can contribute too. As part of this, I am going to get involved [...]]]> Well, better late than never. I thought I would take this chance to set myself some ‘open’ goals for the New Year.

First off I hope to get involved in more FOSS advocacy projects, there are a few about which I hope I can contribute too. As part of this, I am going to get involved with or run a Software Freedom Day Event in September so I will be working towards that over the coming months.

I am also hoping to setup a local user group that can help support and guide people through the world of free software. The aim would be to have the group setup before the software freedom event so that it can be promoted as a source of help and further information. This group would help to form a team to run the event, and would enable people to drop in afterwards to learn more, get help and build a local community that can sustain future events.

Migrate another system. I have two systems at work, (two of many overall) one that runs Windows XP, the other Vista. Well it did until I took a Fedora 10 disk to it.

I do run Linux on some of my desktops and its not my first attempt to migrate this poticular one. Its the easier of the two work systems to do so i decided to give it another go. I am hopeful there will be more success this time. I know of 1 or 2 applications that will require Windows so I am going to build a get out of jail free card Virtual Machine on it. This should allow me to use workarounds if needed rather than to revert the system.

My goal is to have it running Fedora all year, even if I have a Windows VM on it.

I am going to try to blog more this year. It will hopefully be a good way of me to give information to the community that has helped me, and howto’s i have completed things or details of how I have over come issues etc.

So now I guess I should get to it, hope you have a Happy New Year!

After the issue I blogged about the other day, where a webserver was being used to generate spam, we were left with a lot of spam email in the servers mail queue awaiting delivery.

Amongst other things, this was then [...]]]> Here is a quick HowTo / TechTip for deleting all the mail from an exim mail queue!

After the issue I blogged about the other day, where a webserver was being used to generate spam, we were left with a lot of spam email in the servers mail queue awaiting delivery.

Amongst other things, this was then causing a performance hit on the server sending messages. I decided that the few real emails in the queue were on no importance and to just delete the whole lot.

Chances are as a sysadmin, its a job you may have to do at some point. This is how I cleaned out the exim queue on the webserver and then the one on the outbound mail server.

First off, take a look at your queue:

[user@www user]# exim -bp
As the mail is spam we want to delete it, not empty the queue via SMTP as all the spam will sent to people and our server may be blacklisted.

Delete all the mail in the queue run:

[user@www user]# exim -bpru | awk {‘print $3′}
| xargs exim -Mrm > deletedmail.txt
We can now check how many mails were removed by running:

[user@www user]# wc -l deletedmail.txt
13416 deletedmail.txt
[user@www user]#
We have now deleted all 13416 mails in the queue and the server is as good as new. (Remember to fix the loop hole first, if you don’t you will soon have alot of spam in the queue again!)

The deletedmail.txt file will look something like this:

Message 1K3FYb-0000wH-CF has been removed
Message 1K3FYb-0000wH-6l has been removed
Message 1K3FYb-0000wH-3r has been removed
Message 1K3FYb-0000wH-1d has been removed
On the mail server, we want to remove all mail from the webserver only. To do this we modify the command line to grep for the sending address.

[user@mail user]# exim -bpru | grep “” |
awk {‘print $3′} | xargs exim -Mrm > deletedmail.txt
[user@mail user]# wc -l deletedmail.txt
73012 deletedmail.txt
[user@mail user]#
So we have now removed 73012 mails from the mail servers queue. This means in my example here, we have saved the internet from 86428 spam emails.

A few other useful exim queue commands include:

# exim -q # Flush waiting mail
# exim -qf # Flush all mail
# exim -qff # Flush even frozen mail
To remove frozen mail from the local spool, try this…

# exim -bpru | grep “*** frozen ***” | awk {‘print $3′} |
xargs exim -Mrm > deletedmail-frozen.txt

(This works on RHEL/CentOS, [...]]]> Do you run a squid proxy? I do, and have been restarting squid to apply config changes for ages. Turns out that you can just run “service squid reload”, users have no down time and your config changes get applied. Great. Wish I had thought to check that before now…..

(This works on RHEL/CentOS, but any install of squid is capable of this via one command or another)

I will assume you have built a CentOS 4 / 5 Server, have yum [...]]]> This is my quick guide to do an install and basic setup of exim on CentOS. This is not meant as a fully inclusive guide but it will get you on the way. Following this you should get a working exim install.

I will assume you have built a CentOS 4 / 5 Server, have yum working and have logged in as root.

You may want to make sure your up to date…
yum update

Install exim and mail switching tools
yum install exim
yum install system-switch-mail

Switch your MTA & set exim to start on boot
system-switch-mail
service sendmail stop
service exim start
chkconfig exim on
chkconfig sendmail off

Add a root alias, eg: “root: me@example.com”
vi /etc/aliases

You may also wish to add some config to your routers section like this, if you want to relay through a smart host.
vi /etc/exim/exim.conf

Then add this before the “dnslookup:” section.

to_smart_host:
driver = manualroute
domains = ! +local_domains
transport = remote_smtp
route_list = “* mail1.example.com:mail2.example.com;”

Restart exim
service exim restart

To test, send an email
echo “test” |mail -s “$HOSTNAME” me@example.com

Then you can flush the Exim Que and watch the log like this
exim -qff ; tail -f /var/log/exim/main.log

Good luck!