void.gr on IPv6

Since Leaseweb, the hosting company where void.gr’s server is located, isn’t yet ready to provide native IPv6 to dedicated servers, I decided not to wait for them any longer and to set up an IPv6 tunnel to tunnelbroker.net so that I make void.gr accessible over IPv6.

Setting up the tunnel is extremely easy. Having the following in my /etc/rc.conf does the trick:

ip tunnel add he-ipv6 mode sit remote local ttl 255
ip link set he-ipv6 up
ip addr add 2001:470:1f14:e0a::2/64 dev he-ipv6
ip route add ::/0 dev he-ipv6
ip addr add 2001:470:1f15:e0a::1/64 dev eth2

Yes, I know I could have used some of debian’s config files for these parameters…Oh and you “ifconfig” users, time to give up using that ancient tool, it’s time you learn how to use “ip”.

So for you people who have IPv6 connectivity, just try it. The current IP of void.gr is 2001:470:1f15:e0a::1. Ping6 it 🙂

Time is ticking away…bye bye IPv4: http://ipv6.he.net/statistics/

AAAA records with Plesk

Plesk is surely not ready for IPv6. Despite that fact, many people – me included, have the DNS records of their favorite domains managed by Plesk and still want to be able to add some IPv6 records to those.

Some time ago I had posted on my twitter account a link to another blog that had a “hackish way” to add AAAA records to Plesk. I have written a slightly more elegant shell script (to be run by root only) than the one provided by experimentalworks.

First of all you _need_ to alter dns_recs table of the psa database to allow AAAA records:

# mysql -u admin -p psa 
mysql> alter table dns_recs modify column type enum('NS','A','AAAA','CNAME','MX','PTR','TXT','SRV','master','none') NOT NULL default 'A'; 

Then download my plesk-AAAA.sh script and use it like the following example.

To add www.foobar.gr to point to 2001:db8:1001::1

Usage: ./plesk-AAAA.sh [zone serial]
#./plesk-AAAA.sh foobar.gr www 2001:db8:1001::1
#./plesk-AAAA.sh foobar.gr ipv6 2001:db8:1001::1 12

Known bug/feature:
If you add a record without adding a serial, for the soa record, at the end, it will add the serial of the domain in the form:


So if you add two ipv6 hosts in the same day for the same domain you _have_ to manually add a serial >10 for the second host (and so forth).

For the ones who don’t like downloading but would like to see the script source, here it is:

  1 #!/bin/sh
  3 usage () {
  4         echo "Usage: $0 <domain> <hostname> <v6 IP> [zone serial]"
  5         echo "Usage: $0 foobar.gr www 2001:db8:1001::1"
  6         exit 1
  7 }
  9 if [ $# -lt 3 ]; then
 10         usage
 11 fi
 12 DOMAIN=$1
 14 v6IP=$3
 15 INPUT_SERIAL=${4:-10}
 16 FULLHOST="$2.$1."
 18 ADMIN_PASS=`cat /etc/psa/.psa.shadow`
 19 MYSQL_BIN_D=`grep MYSQL_BIN_D /etc/psa/psa.conf | awk '{print $2}'`
 20 PRODUCT_ROOT_D=`grep PRODUCT_ROOT_D /etc/psa/psa.conf | awk '{print $2}'`
 21 SERIAL=`date +%Y%m%d${INPUT_SERIAL}`
 22 mysql="${MYSQL_BIN_D}/mysql -N -uadmin -p${ADMIN_PASS} psa"
 24 query1="SELECT dns_zone_id FROM dns_recs where host like \"$DOMAIN%\" LIMIT 0,1"
 25 ZONE_ID=`echo "$query1" | $mysql`
 26 echo "ZONE_ID=$ZONE_ID"
 27 query2="INSERT INTO dns_recs (displayHost, host, displayVal, val, type, dns_zone_id) VALUES ('$FULLHOST', '$FULLHOST', '$v6IP', '$v6IP', 'AAAA',$ZONE_ID)"
 28 echo "$query2" | $mysql
 30 query3="UPDATE dns_zone SET serial=\"$SERIAL\" WHERE id=$ZONE_ID LIMIT 1;"
 31 echo "$query3" | $mysql
 33 echo "REBUILDING zone file for $DOMAIN"
 34 $PRODUCT_ROOT_D/admin/sbin/dnsmng update $DOMAIN

The script has been tested with bash and zsh. I have no idea whether it works under any other shells.
The script probably won’t delete your databases, but…use it at your own risk 🙂 I hope someone finds it useful.

Greek spammers email addresses blacklist

In the beginning of the year I announced my RBL for Greek spam emails. The blacklist is growing larger by the day, thanks to some really kind people forwarding me their Greek spam emails, and has reached more than 120 IP addresses of verified Greek spammers.This alone though is not enough.

Some spammers use their aDSL lines which have dynamic IPs to send their massive email “newsletters”. These people are split into 2 sub-categories. The ones that use their own PC as an SMTP server and the ones who use their ISP’s mail server as SMTP. I’ve tried to complain to some of their ISPs…some replied back saying that they were willing to look into the issue (but did nothing at all in the end) and others did not even reply to me. For both sub-categories, GrRBL is ineffective since I can’t add dynamic IPs in the blacklist nor can I add the IPs of the email servers of those major Greek ISPs.

Another category of spammers is the one that uses their gmail/yahoo accounts to send their emails. GrRBL is ineffective for this category as well since I can’t add gmail/yahoo to the blacklist…

So there was no alternative but to gather all those email addresses of these 2 categories above and add them to a new blacklist, one that will contain email addresses. I use this blacklist with my spamassassin configuration to eliminate Greek spam that GrRBL can’t. Each time I receive (or someone forwards me) a new Greek spam, I add the “From:” email address to this new blacklist. This new blacklist grows far more aggressively than GrRBL since it’s a lot easier to gather the data and already has more than 140 addresses.

There are two available formats of the blacklist, one ready for use by spamassassin and another one with clear formatting ready to be used even by SMTPs to drop these spam emails without even touching your inbox.
The blacklist is currently only distributed to a group of well trusted people and it is available only through rsync with a username/password.

I don’t want to make the list completely public yet, but if you are interested you can request it at the contact email of GrRBL and I will reply to you about accessing it.

If you need a good tool to check a host again some RBLs, adnsrblcheck by Yiorgos Adamopoulos is the way to go (and it includes GrRBL!)

Using OpenVPN to route a specific subnet to the VPN

I have an OpenVPN server that has the push "redirect-gateway" directive. This directive changes the default gateway of the client to be the OpenVPN server, what I wanted though was to connect to the VPN and access only a specific subnet (eg. through it without changing the server config (other people use it as a default gateway).

In the client config I removed the client directive and replaced it with these commands:

What the previous lines do:
tls-client: Acts as a client! (“client” is an alias for “tls-client” + “pull” … but I don’t like what the pull did–>it changed my default route)
ifconfig The tun0 interface will have ip on our side and on the server side. The IPs are not random, they are the ones OpenVPN used to assign to me while I was using the “client” directive.
route Route all packets to on the tun0 interface. In order to access services running on the OpenVPN server ( I needed a route to them.
route Route all packets to on the tun0 interface

A traceroute to now shows that I accessing that subnet through the vpn.

iftraffic.pl: perl script to measure in/out traffic in realtime

During some QoS tests on Linux I needed to measure the traffic of the system in realtime without being able to compile any new software on it. The system had already perl installed so I googled to find a script that could monitor in/out traffic of an interface. The first script I found was this: http://perlmonks.org/?node_id=635792

While it’s actually doing what it says, it only runs just once. I wanted the script to run for a period of time. So I changed it a bit.
Here’s the outcome:
my $dev=$ARGV[0];
sub get_measures {
my $data = `cat /proc/net/dev | grep "$dev" | head -n1`;
$data =~ /$dev\:(\d+)\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+\d+\D+(\d+)\D+/;
my $recv = int($1/1024);
my $sent= int($2/1024);
return ($recv,$sent);
my @m1 = get_measures;
while(1) {
sleep 1;
my @m2 = get_measures;
my @rates = ($m2[0] - $m1[0], $m2[1]-$m1[1]);
foreach ('received' , ' transmit') {
printf "$_ rate:%sKB",shift @rates;
print "\n";

I’ve changed it so that it’s:
a) running continuously until someone presses ctrl+c to stop it,
b) parsing the /proc/net/dev output instead of the ifconfig output. I think this is more efficient/fast than parsing the ifconfig output.

Sample output:

$iftraffic.pl eth0
received rate:1564KB transmit rate:71KB
received rate:1316KB transmit rate:44KB
received rate:1415KB transmit rate:48KB
received rate:1579KB transmit rate:76KB

I am sure that someone with more insight into perl than me can make it even more efficient.

You can also download a version with comments that I made so that one can make the script run for X number of repetitions instead of running until someone stops it.
Download: iftraffic.pl