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I am performing a traceroute (I also tried a curl out of curiosity, that just stalls) on a publicly available website (so I know my computer should be able to and is allowed to reach it). However, when I perform the traceroute it stops at the location I believe to be the location from which the website is served (a whois on this IP shows the registered company address of the parent company which, oddly, the daughter-site denies it is directly affiliated with -- though there could quite easily be legit reasons for this), it goes through another 16 or so hops to get to its final destination, all of which are asterisked out...

Now, with my fairly limited knowledge of this stuff, I've come to believe that the most likely explanation is there's some sort of IP or port filtering in place on the internal network which is blocking the traceroute probes, but I'm wondering if there's a way to figure out why these probes are being blocked, and what the exact filter/firewall settings are, without actually gaining access to anything I shouldn't be (i.e. making sure I only retrieve information that's already being publicly served from the server).

I've tried various different traceroute flags but so-far have had no joy. For example, the -p flag gives:

Cannot handle `-p' option with arg `[sitename.co.uk]' (argc 2)

I'm using Fedora 24.

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You can try digging into man traceroute, there is explanation of asterisked hosts in traceroute output.

It basically means that router either not sending ICMP "time exceeded" (due to firewall rules, some specific software, etc.) or TTL of packet is too small and can't get back to you.

I guess blocking some types of ICMP packets can be part of security policy of company/datacenter that don't want someone to know their internal setup.

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Some of ISP's use Private IP address space to route traffic inside their networks. Then they filter private IP addresses on the network borders. That's why you can't see routers inside those networks if you are outside them. It often is used with MPLS technology.

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