[bash]
time tcpdump -ieth0 -c 100 -nn dst 70.164.19.160 and ‘tcp[13] & 2 == 2′ | awk ’split($3,ip,”.”) {print ip[1] “.” ip[2] “.” ip[3] “.” ip[4]}’| sort | uniq -c | sort -n
[/bash]

[bash]
#!/bin/bash

SEARCHSTRING=`echo $1|cut -d. -f1|sed ’s/ /_/g’|sed ’s/-/_/g’|sed ’s/_/+/g’`
IMDBURL=`curl -iIs -A “Mozilla/5.0″ “http://www.google.com/search?&q=site+www.imdb.com+$SEARCHSTRING&btnI” | grep Location | awk {‘print $2′}`
echo $IMDBURL
[/bash]

For most of my Linux life I have been in the Red Hat camp. First Red Hat itself, then CentOS. At work we run CentOS, the box this blog runs on is running CentOS. I like rpm better than dpkg, though I think apt is better than yum. I used Debian as a server for a while and I like it for a number of reasons. The huge package repository was great and there was a certain amount of polish to be found with Debian in general. I liked Debian. I also got burned when Debian broke their repository several times which broke my servers. The openssl fiasco was the thing that really drove me away though. Such a lapse in security really made me doubt that Debian was a good distro for my servers. I replaced all of my Debian servers with CentOS after that and did not look back. I occasionally used Debian for special projects. When I needed a slim distro to use as a base for an MAME arcade machine I chose Debian. My first XBMC box was Debian (if you don’t count xboxes).

About a year ago I was building a new media server for my home network. This machine would store all of my music, movies, pictures and other media in a central location so that all of my xbmc instances could access my entire collection over the network. I wanted this machine to have a large amount of space, support samba, nfs, http and other typical stuff. I also wanted to run music player daemon (MPD) and play music in various locations around the house or over the network. My previous media server, which was really just an old PC, ran CentOS and performed all of these tasks fairly well. One thing that was difficult on CentOS though was using MPD. There is an MPD package in the RPMForge repo but it falls behind the the MPD sources quickly. Building MPD from source on CentOS was a pain because so many of the dependencies also had to be compiled from source which meant that this was a lot of work. This type of situation is typical for a Redhat / CentOS install.

Because Red Hat aims for supportability many of their packages are out of date. Their kernel can fall behind in important ways, IPv6 is a good example of this. Red Hat kernels are missing many IPv6 related features when compared to the mainline Linux kernel. Good IPv6 support is something I need and this forced me to maintain my own kernel packages on CentOS. Not a huge burden, but not ideal either. The less time I have to spend compiling and configuring things the more time I have to do other stuff.

What does all of this have to do with Ubuntu server? Well, I decided that for this media server I would try something new. I would give Ubuntu server a try. I’d been using Ubuntu on the desktop for years and had been happy, perhaps the server distro was just as good. I installed the 64 bit version of Ubuntu server on a Via Nano based system with 4 disks using RAID w/ LVM. The system is a file and print server running CUPS, Samba and NFS. It is an MPD server serving music throughout my house, deck and the Internet via Icecast. This server also runs Cacti in order to collect and display stats from a bunch of other servers I run at various locations. This server has been running for about a year now and I have to say that I am very pleased with Ubuntu server.

Ubuntu server offers many of the benefits of Debian, a large binary repo (based on Debian testing) and a big community. Ubuntu also has a 6 month release cycle for new stable releases, Debian has a history of taking forever to release a new stable release. You can run testing or unstable but there is risk associated with that. Ubuntu’s 6 month release cycle is a great feature. I have not had a problem upgrading to each new release either. Ubuntu also offers some of the things Redhat offers. Namely, long term commercial support. Canonical does things a bit differently than Red Hat in regard to support. Canonical supports what they call Long Term Releases. These releases get 3 years of support on the desktop and 5 years on servers. You can buy various levels of support from Canonical on the Ubuntu website. Costs seem to be on par with Red Hat though the pricing model is somewhat different. Commercial support is of no interest to me though. I support myself. I do think it is good that Redhat and Novell have some competition though so Canonical providing support is a very good thing. Canonical is approaching the commercial Linux space differently than Novell and Red Hat. I think this is a good thing as well. Red Hat and Novell are buried in old school brick and mortar software company dynamics. Canonical seems to be doing things in a more “web 2.0″, new Internet sort of way. I like that.

I recently converted the last of my home servers to Ubuntu from CentOS. This machine acts as my home firewall, VPN server, IPv6 tunnel end point and other networking related functions. Ubuntu performs the functions that are required of this role very well without having to compile my own kernel, iptables or other tools. I appreciate that very much. Ubuntu has given me more time to focus on my projects, not fighting with my OS or maintaining my own packages in order to be able to do what I want to do. I like that a lot too.

Ubuntu sits somewhere between the wild west that can be the world of Debian (or Gentoo perhaps) and the conservative environment that is made by Red Hat. I think this is a good place to be.

Thanks Canonical. Ubuntu server is hella good

Sent from my iPhone

[bash]
#!/bin/bash
#
# Matt’s IP change checker, DNS updater, he.net tunnel endpoint updater, etc, etc.
#
# Local Vars:
CURRENTIP=`/sbin/ifconfig eth0 | /bin/awk ‘/inet addr/ { sub(/inet addr:/, “”); print$1}’`
LASTIP=`/bin/cat /var/tmp/lastip`
[/bash]

Here are some variables for updating the he.net tunnel settings. I got this information from http://ipv6.he.net/certification/faq.php
he.net’s tunnelbroker service is awesome! Thanks he.net! Be aware that MD5HASH != MD5SUM in this instance.

[bash]
# Vars for he.net tunnel setup
IPV4ADDR=”$CURRENTIP”
MD5PASS=”YOURMD5HASHEDPASSWORDGOESHERE”
USERID=”YOURHENETUSERIDGOESHERE”
GTUNID=”TUNNELID”
[/bash]

Now we compare the CURRENTIP to LASTIP. If they are the same then the script exits.

[bash]
if [ "$CURRENTIP" = "$LASTIP" ]; then
exit
[/bash]

If they are different the script does a bunch of stuff starting re-running my firewall script. I use a custom iptables script that is probably not very useful to most people but I can provide it if people are interested in how I do stuff. Next the script restarts openvpn. I have some static openvpn tunnels and they need to be restarted when my IP address changes. Next the script updates DNS. In order for this to work your name server must allow dynamic updates and you should secure the transaction using keys. This is all pretty straight forward using BIND so I’m not going to get into how to do it here but if you have questions feel free to ask and I’ll help if I can.

[bash]
else
# Update the LASTIP tmp file to reflect new IP address
echo $CURRENTIP > /var/tmp/lastip
# Re-Run my firewall script so rules use new IP address
/etc/firewall/v4firewall.sh
# Restart static openvpn tunnels
/etc/init.d/openvpn restart
# update planetfoo.org zone with leela’s new IP
/usr/bin/nsupdate -k /PATH/TO/KEY < server "Your DNS Server IP address goes here"
zone planetfoo.org
update delete leela.planetfoo.org A
update add leela.planetfoo.org 60 A $CURRENTIP
send
EOF
# update home.planetfoo.org with ns's new IP
/usr/bin/nsupdate -k PATH/TO/KEY < server "Your DNS Server IP address goes here"
zone home.planetfoo.org
update delete ns.home.planetfoo.org A
update add ns.home.planetfoo.org 300 A $CURRENTIP
send
EOF
[/bash]

Next the script updates the IPv6 tunnel configuration with he.net's tunnelbroker service, restarts the tunnel in order to get IPv6 connectivity working again.

[bash]
# update the he.net tunnel configuration
/usr/bin/curl -k https://ipv4.tunnelbroker.net/ipv4_end.php?ipv4b=$IPV4ADDR\&pass=$MD5PASS\&user_id=$USERID\&tunnel_id=$GTUNID
sleep 5
# Stop the current tunnel
/etc/init.d/ipv6-tunnel stop $LASTIP
sleep 5
/etc/init.d/ipv6-tunnel start $CURRENTIP
[/bash]

The last thing the script does is send an email to my phone letting me know that my IP address has changed. This is kind of a fail safe in case the DNS changes don't go through or something else happens. At least I have the new IP address.

[bash]
# Send email to myself with new IPv4 address
echo $CURRENTIP | /bin/mail -s "Leela's IP New IP Address" YOUR_EMAIL_ADDRESS_GOES_HERE
fi
[/bash]

Download Complete Script

[bash]
apt-key adv –keyserver keyserver.ubuntu.com –recv-keys $Key
[/bash]
Where $key == the gpg key id. The key id is shown in the error message you get when running apt-get update after adding a new repository. For example:
[bash]
GPG error: http://download.virtualbox.org karmic Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY DCF9F87B6DFBCBAE
[/bash]
DCF9F87B6DFBCBAE is the key ID for the virtualbox karmic repository. So doing this:
[bash]
apt-key adv –keyserver keyserver.ubuntu.com –recv-keys DCF9F87B6DFBCBAE
[/bash]
imports the correct key.

To reboot the box:
[bash]
echo 1 > /proc/sys/kernel/sysrq
echo b > /proc/sysrq-trigger
[/bash]
To shut it down:
[bash]
echo 1 > /proc/sys/kernel/sysrq
echo o > /proc/sysrq-trigger
[/bash]