GTT blocking IPv4 address

Ryan Hamel administrator at
Wed Jan 4 04:21:35 UTC 2023

Confirmed it with a router at AS8100, static routing towards GTT
results in a blackhole and works just fine, which means either
the IP address is null routed on GTT's network at the request of MIT (got to
give them the benefit of the doubt) or they are knowingly blocking Tor.

Ryan Hamel

-----Original Message-----
From: NANOG < at> On Behalf Of Neel
Sent: Tuesday, January 3, 2023 7:49 PM
To: nanog at
Subject: GTT blocking IPv4 address


I am a customer of ReliableSite in their New Jersey location, and RS uses
GTT as a transit ISP, along with Tata and Comcast.

GTT appears to be blocking the IPv4 address, and RS' BGP uses
GTT for

neel at t1:~ % traceroute
traceroute to (, 64 hops max, 40 byte packets
  1  45.150.XXX.1 (45.150.XXX.1)  4.828 ms  4.557 ms  5.916 ms
  2  * * *
neel at t1:~ %

Hop #2 which is generally the transit provider, GTT (which handles this

Note: 45.150.XXX.1 is because it's a subnet I brought in, this is the only
ReliableSite hop.

The doesn't appear to be blocked as a whole, only that See below:

neel at t1:~ % traceroute
traceroute to (, 64 hops max, 40 byte packets
  1  45.150.XXX.1 (45.150.XXX.1)  0.241 ms  0.220 ms  9.362 ms
  2 (  1.605 ms  0.853 ms
1.173 ms
  3 (  5.488 ms  6.471 ms  1.451 ms
  4 (  1.604 ms
1.726 ms *
  5 (  1.802 ms
1.771 ms  1.708 ms
  6 (  7.082 ms
7.268 ms  7.249 ms
  7 (  7.017 ms  7.247 ms  6.987 ms
  8 (  7.010 ms  7.001 ms
6.996 ms
  9 (  7.033 ms  7.294 ms (  7.073 ms
10 (  9.011 ms  7.484 ms  7.551 ms
neel at t1:~ %

As you can see here, GTT handles other IPs fine as seen in hop

ReliableSite says they don't block the IP address, but I don't have any
contact at GTT or MIT.

My home ISP, Lumen/CenturyLink/Level 3 does not block is a Tor directory authority IP, which is usually a phonebook of
Tor relays. There are 9 in the world and the other 8 are unblocked from

Yes, I know Tor is all this 'bad stuff' but the reality is that 99% of Tor
users use it like a VPN, speaking as a Tor exit operator and code
contributor myself. Exit abuse complaints were super common 5-8 years ago
but are now super rare.

If someone works at GTT, can be unblocked?




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