How to ping a computer connected via GPRS from another computer, also connected via GPRS (maybe even another mobile operator)?

10101010010001001101001112012-02-03 10:07:00

mobile connection

1010101001000100110100111, 2012-02-03 10:07:00

In other words, how to establish a "p2p connection" using the ICMP protocol between two mobile terminals?

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8 answer(s)

isden, 2012-02-03
@isden

I see 2 options:
1. Simple - DynDNS on client computers. Those. with any change of ip, we can still refer to the host by name.
2 More difficult - some third intermediary node with a known fixed address and a VPN server on board.

Evengard, 2012-02-03
@Evengard

I see only an option with Hamachi or similar (VPN). The thing is that the mobile Internet OPSOs are usually diligently NAT-yat. This means that you will have to break through 2 NATs (at least 1 on your side, 1 on the other) or even more.
Breaking through so many NATs without GPRS does not always work out ...
So only VPN.

Maxim Kuzovlev, 2012-02-03
@KY3EH

There seems to be something similar here .

Maxim, 2012-02-03
@Maxim_ka

Install the teamviewer on both machines, and you will be able to see each other, in which case, and again for verification.

Disasm, 2012-02-03
@Disasm

First, through some server, determine each other's external IP, and then throw ICMP packets into these IPs from terminals.

Vitaly Peretyatko, 2012-02-04
@viperet

en.wikipedia.org/wiki/STUN
network protocol (....) is used to establish a UDP connection between two hosts when they are both behind a NAT router.
It is possible that it will also be possible to apply for ICMP, well, at least they will recognize their external IP hosts. RFC describing ICMP NAT traversal www.faqs.org/rfcs/rfc5508.html
NAT uses the packet's ICMP Query Id field for Sender-to-Destination matching, just like a port in UDP. That is, by sending a packet from one H1 host to the external IP of the second H2 host with some given ID, our nat will miss it and will wait for a response from H2 with the same ID, and it will pass it to H1. The only problem is that this response will form the router behind which H2 sits, and most likely our NAT will immediately remove the IP-> ID mapping from its tables and thus we will not be able to receive a packet from H2 ...
The task is difficult but interesting ...

ValdikSS, 2012-02-04
@ValdikSS

samy.pl/pwnat/
Here. Something like what disasm wrote. It definitely works.

w66fer, 2012-02-07
@w66fer

I myself have a similar task, I will try the following: I will
buy a router with dd-wrt support.
I'll set up a VPN server on it.
I will bind it to DynDNS.
I'll turn on my cell phones.
In theory, everything is simple and should work, in practice ... hmm ... I'll find out.