Ask the Expert

  • 1.  What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-03-2021 05:34
    If I like to reach 192.168.0.2 via ISP which does not provide my any information except the its peer IP with me, how can I identify whether 192.168.0.2 is reachable from ISP ?

    I did the following, and some time I got the Destination unreachable from the ISP, so I can tell the destination I like to reach is unreachable from ISP.
    [edit]
    root@Branch1# run traceroute 192.168.0.2 no-resolve
    traceroute to 192.168.0.2 (192.168.0.2), 30 hops max, 40 byte packets
     1  172.16.1.6  5.590 ms !N  2.315 ms !N  1.855 ms !N
    ​

    But sometimes for some reason, just nothing returns.  just like the following

    root@Branch1# run traceroute 192.168.0.2 no-resolve
    traceroute to 192.168.0.2 (192.168.0.2), 30 hops max, 40 byte packets
    

    Any other way can help to identify the issue is on my side, or on ISP side ?

    thanks !!



  • 2.  RE: What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-03-2021 05:38
    The address 192.168.0.2 is NOT allowed to route on the internet.  This is part of one of the prefixes reserved in rfc 1918 for internal private networks only.
    192.168.0.0/16
    10.0.0.0/8
    172.16.0.0/12

    These address ranges are private ip addresses usable only inside non-internet routed networks.

    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
    http://puluka.com/home
    ------------------------------



  • 3.  RE: What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-04-2021 18:23
    100% agreed with Steve!
    with that in mind I believe the IPs represented on this thread are selected randomly for lab purposes. This issue is tracked  here as well.


  • 4.  RE: What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-05-2021 16:29
    thanks a lot !!

    The first time I posted, I did not see my post, so I posted it again. That is why duplicated.


  • 5.  RE: What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-05-2021 16:30
    thanks a lot !!


  • 6.  RE: What is the best way to identify whether my ISP can reach the network I need to reach ?

    Posted 05-05-2021 16:29
    Networks that make up "the internet" do not exchange, therefore route, RFC1918 addresses between them.  These are reserved routes for private/internal use, so it's expected behavior that when performing a traceroute from your network outbound to the internet that it would fail.