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I am running Debian 9 with kernel 4.9.0-4-amd64. My internet access is through my mobile supplier in 4G by sharing connection with my phone. I fail to ping my public IP address.

I get my IP on this site:

http://checkip.dyndns.com/

and the command 

ping 37.168.204.137

returns

PING 37.168.204.137 (37.168.204.137) 56(84) bytes of data.
^C
--- 37.168.204.137 ping statistics ---
6 packets transmitted, 0 received, 100% packet loss, time 5124ms
Smilia
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    You need to include your firewall rules, or conclusively demonstrate it's deactivated. – roaima Oct 22 '17 at 09:20
  • That you need to check the public address via dyndns.com makes me guess your operator is doing Network Address Translation and provides a private network address to you. If this is the case, the public address is shared by many of your operator's customers and the ping packets are probably filtered by your operator. – Johan Myréen Oct 22 '17 at 10:11
  • @Johan Dyndns is also used for public IP addresses that are dynamic rather then static. Although it is quite possible this scenario uses CGNAT it's not a requirement. – roaima Oct 22 '17 at 10:28

1 Answers1

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Usually, such mobile IP addresses matches one of your mobile provider's Internet gateways.

These gateways are central locations linking the operator's internal network with the Internet: all mobile users shares the same set of gateways. Because of this system IP-based geolocation also usually fails with cellphones as IP-geolocation localizes the provider's gateway instead of the cellphone user.

What you "discovered" is that your operator has disabled ping response on his Internet gateway, at least for request coming from his 4G users (assuming that you can ping other servers).

WhiteWinterWolf
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  • Tren... How can I geolocate a mobile device via web? – Víctor Carreras Oct 22 '17 at 11:53
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    @VíctorCarreras: You must ask the permission ;) ! You can check this StackOverflow question: [How does web browser geolocation work?](https://stackoverflow.com/q/3633879/3248253), the point is that IP based geolocation is unusable for mobile devices so you must a specific API provided by the cellphone system (and any software in-between such as the browser) and user's permission to access this API. – WhiteWinterWolf Oct 22 '17 at 12:00