Hi nanog mailing list,
Keep in mind that I am not a practicing network engineer, although I do
have interest and knowledge on networking topics. I do not work for
Verizon. I subscribe to Verizon FiOS, but not Verizon Wireless or
Verizon's enterprise services.
The Tor "directory" server with the IPv4 address 86.59.21.38 has been
blocked by Verizon's AS701 backbone for a few months now. AS701 provides
Internet connectivity to Verizon FiOS and Wireless.
The design of Tor is that even though anyone can set up a "relay", there
are a few central directory servers which clients go to first to get a
list of relay servers and build a circuit (which is a path of three
relays to reach a destination). A more descriptive overview of Tor is
available here: https://www.torproject.org/about/overview.html.en .
While I can still access other Tor directory servers from Verizon FiOS
as running Tor as a client or relay does not require every directory
server be unblocked, blocking one of them could possibly mean breaking
some part of the Internet for a Verizon customer.
A traceroute to 86.59.21.38 from FiOS shows that I can get through
verizon-gni.net which is Verizon's internal FiOS network, but not
ALTER.NET, which is Verizon's UUNet backbone:
neel@xb2:~ % traceroute 86.59.21.38
traceroute to 86.59.21.38 (86.59.21.38), 64 hops max, 40 byte packets
1 unknown (192.168.1.1) 1.128 ms 0.780 ms 0.613 ms
2 lo0-100.NYCMNY-VFTTP-401.verizon-gni.net (173.68.77.1) 1.001 ms
3.632 ms 0.900 ms
3 B3401.NYCMNY-LCR-22.verizon-gni.net (100.41.137.96) 2.291 ms
B3401.NYCMNY-LCR-21.verizon-gni.net (100.41.137.94) 3.172 ms
4.046 ms
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
^C
neel@xb2:~ %
In a normal traceroute, I would see ALTER.NET on hop 5. Also, this
filtering is not a subnet filtering. A traceroute to 86.59.21.1 works:
neel@xb2:~ % traceroute 86.59.21.1
traceroute to 86.59.21.1 (86.59.21.1), 64 hops max, 40 byte packets
1 unknown (192.168.1.1) 0.863 ms 0.757 ms 0.579 ms
2 lo0-100.NYCMNY-VFTTP-401.verizon-gni.net (173.68.77.1) 1.010 ms
1.545 ms 1.034 ms
3 B3401.NYCMNY-LCR-22.verizon-gni.net (100.41.137.96) 3.616 ms
B3401.NYCMNY-LCR-21.verizon-gni.net (100.41.137.94) 5.696 ms
10.062 ms
4 * * *
5 0.et-5-1-5.BR3.NYC4.ALTER.NET (140.222.2.127) 3.492 ms 3.506 ms
2.996 ms
6 204.255.168.118 (204.255.168.118) 8.462 ms 7.479 ms 7.252 ms
7 144.232.4.84 (144.232.4.84) 5.041 ms 4.688 ms
sl-crs3-lon-0-6-3-0.sprintlink.net (144.232.9.165) 71.865 ms
8 sl-crs2-lon-0-0-3-0.sprintlink.net (213.206.128.181) 72.214 ms
73.579 ms 72.339 ms
9 213.206.129.142 (213.206.129.142) 81.390 ms
sl-crs4-ams-0-7-0-3.sprintlink.net (213.206.129.139) 85.854 ms
93.238 ms
10 217.149.47.46 (217.149.47.46) 79.004 ms 85.669 ms 79.392 ms
11 ams5-core-1.bundle-ether1.tele2.net (130.244.82.54) 86.507 ms
78.374 ms 77.740 ms
12 ams-core-2.bundle-ether9.tele2.net (130.244.82.57) 79.642 ms
77.926 ms 81.515 ms
13 wen3-core-2.bundle-ether15.tele2.net (130.244.71.47) 105.400 ms
105.089 ms 109.751 ms
14 tele2at-bundle2-vie3.net.uta.at (212.152.189.65) 122.716 ms
110.820 ms 114.354 ms
15 86.59.21.1 (86.59.21.1) 106.389 ms * 105.379 ms
neel@xb2:~ %
I had posted this finding on Tor's mailing list
(https://lists.torproject.org/pipermail/tor-relays/2018-May/015218.html).
I am posting here as (I believe) Verizon NOC people are more likely to
read NANOG mailing lists than Tor mailing lists, although this post is
modified from the original because not all network engineers may know
how Tor works.
From Tor developer Roger Dingledine (at the Tor mailing list), the
reason why Verizon blocked 86.59.21.38 in the first place is probably
the WannaCry ransomware, and the VZ NOC didn't realize it was a Tor IP
address (or how Tor works), and then whoever did this block forgot about
it and moved on. I can understand that you all may not know how Tor
works either, so I included an overview link above. It could also be
possible that it's the NN repeal (but less likely since it is on the
level of UUNET not FiOS).
I also contacted the operator of 86.59.21.38 as well as Verizon FiOS
support, and neither were of much help (the former is obvious as he's
Austrian).
Well, thank you for reading.
Best,
Neel Chauhan
===
https://www.neelc.org/
