Mysteriously unreachable websites

Today i solved a great annoyance i had for a loooong time... I couldn't access quite many websites:

www.python.org
www.ubuntu.com (No, i am NOT an ubuntu user. It is just that that i couldn't reach their website)
www.lilypond.org
www.ubuntuforums.org
www.delilinux.de

and a whole lot of other domains. I have regarded it as mystery and blamed ISP for that... Until today.

Today, i decided to look at them more closely and my quest was to find similarities between these hosts.

The whole log of how did i diagnose and fix it (maybe oververbose as always):


#This is my router box running Slack10.2
#First, i tried to nslookup and then follow the packets
root@EN6350:/var/log# nslookup python.org
Server: 86.100.0.8
Address: 86.100.0.8#53

Non-authoritative answer:
Name: python.org
Address: 82.94.237.218
root@EN6350:/var/log# traceroute python.org
traceroute to python.org (82.94.237.218), 30 hops max, 38 byte packets
1 123.76.34.95 (123.76.34.95) 2990.280 ms !H 2993.109 ms !H 2999.948 ms !H
root@EN6350:/var/log# traceroute 82.94.237.218
traceroute to 82.94.237.218 (82.94.237.218), 30 hops max, 38 byte packets
1 123.76.34.95 (123.76.34.95) 2995.091 ms !H 2990.231 ms !H 2999.924 ms !H
#This is fake /|\, my gateway's ip is different
#nslookuping once again, to see possible similarities
root@EN6350:/var/log# nslookup lilypond.org
Server: 86.100.0.8
Address: 86.100.0.8#53

Non-authoritative answer:
Name: lilypond.org
Address: 82.94.241.173
root@EN6350:/var/log# nslookup ubuntuforums.org
Server: 86.100.0.8
Address: 86.100.0.8#53

Non-authoritative answer:
Name: ubuntuforums.org
Address: 82.211.81.186
root@EN6350:/var/log# nslookup ubuntu.com
Server: 86.100.0.8
Address: 86.100.0.8#53

Non-authoritative answer:
Name: ubuntu.com
Address: 82.211.81.166
#So, strangely, all of nonreachable hosts are in 82.0.0.0/8 netmask.
#Let's look at route and iptables
root@EN6350:/var/log# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
82.0.0.0 * 255.0.0.0 U 0 0 0 eth1
loopback * 255.0.0.0 U 0 0 0 lo
default 82.135.162.1 0.0.0.0 UG 1 0 0 eth1
#82.0.0.0 route causes all packets sent to some ip address which starts with 82, be sent to null
#So i will delete that route.
root@EN6350:/var/log# route del -net 82.0.0.0 netmask 255.0.0.0 dev eth1
#Now, let's try tracerouting packets
karolis@EN6350:~$ traceroute python.org
traceroute to python.org (82.94.237.218), 30 hops max, 38 byte packets
1 c01.int.balticum.lt (212.59.18.1) 8.700 ms 10.213 ms 9.128 ms
2 c02.int.balticum.lt (86.100.2.17) 62.339 ms 40.145 ms 9.255 ms
3 e01.int.balticum.lt (86.100.2.25) 10.151 ms 10.296 ms 9.614 ms
4 213.226.138.245 (213.226.138.245) 13.482 ms 12.103 ms 14.310 ms
5 213.226.156.60 (213.226.156.60) 232.569 ms 237.165 ms 159.932 ms
6 s6-0-0.11-8-0.ar4.DEN2.gblx.net (208.51.117.249) 196.053 ms 362.947 ms *
7 so1-0-0-2488M.ar1.AMS1.gblx.net (67.17.65.242) 285.953 ms 361.452 ms 242.792 ms
8 * XS4ALL.so-7-0-0.nar1.AMS1.gblx.net (146.82.33.178) 484.540 ms 282.054 ms
9 0.so-6-0-0.xr1.3d12.xs4all.net (194.109.5.1) 249.593 ms 141.258 ms 261.868 ms
10 0.so-3-0-0.cr1.3d12.xs4all.net (194.109.5.58) 356.662 ms 210.328 ms 298.223 ms
11 dinsdale.python.org (82.94.237.218) 91.372 ms 290.529 ms 276.604 ms

So i solved this problem only after about a year since it appeared... Because I couldn't imagine why those sites wouldn't work. But it's better later than never, I guess