title: Erroneous traceroutes from certain GCP regions
body: <p>Can anyone explain why I receive seemingly erroneous traceroute results from some GCP regions?</p>
  
  <p>I am running network analysis from Google Cloud Compute instances in various regions to our own data centres to verify our customer experience.</p>
  
  <p>Here is a test site to show the issue:</p>
  
  <pre><code>$ ping www.bbc.co.uk
  PING www.bbc.net.uk (212.58.249.210) 56(84) bytes of data.
  </code></pre>
  
  <p>I get the following traceroute from asia-east1-b:</p>
  
  <pre><code>asia-east1-b:~$ traceroute 212.58.249.210
  traceroute to 212.58.249.210 (212.58.249.210), 30 hops max, 60 byte packets
   1  108.170.227.202 (108.170.227.202)  152.419 ms 209.85.255.194 (209.85.255.194)  155.181 ms 72.14.239.154 (72.14.239.154)  157.535 ms
   2  216.239.58.130 (216.239.58.130)  248.054 ms 72.14.232.71 (72.14.232.71)  160.910 ms 209.85.247.4 (209.85.247.4)  164.240 ms
   3  216.239.57.197 (216.239.57.197)  181.224 ms 216.239.58.255 (216.239.58.255)  176.807 ms 216.239.57.197 (216.239.57.197)  180.841 ms
   4  172.253.65.165 (172.253.65.165)  252.485 ms  252.262 ms *
   5  216.239.57.236 (216.239.57.236)  247.640 ms 209.85.250.90 (209.85.250.90)  243.427 ms 216.239.57.236 (216.239.57.236)  247.579 ms
   6  74.125.242.112 (74.125.242.112)  249.928 ms  247.138 ms  244.123 ms
  </code></pre>
  
  <p>However, from europe-west2-b I get no route:</p>
  
  <pre><code>europe-west2-b:~$ traceroute 212.58.249.210
  traceroute to 212.58.249.210 (212.58.249.210), 30 hops max, 60 byte packets
   1  * * *
   2  * * *
   3  * * *
   4  * * *
   5  * * *
   6  * * *
   7  * * *
  </code></pre>
  
  <p>I can use curl and retrieve content successfully, so the route is valid and working.</p>
  
  <p>I see this same issue with various hosts and about half of the GCP regions, seemingly at random around the world.</p>
  
  <p>Including map of where we have unknown routes (red).</p>
  
  <p><a href="https://i.stack.imgur.com/UU3Q3.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UU3Q3.jpg" alt="enter image description here"></a></p>