My ISP provides me with an ethernet cable which I connect to my TP-Link router to set up my home network.

I have assigned a static local IP of to my computer which i wish to make public.

Now the problem is that my router WAN IP is different from my public IP

public IP WAN IP

so of course port forwarding does not work (It does work locally though)

I suspect that there is another router involved which belongs to my ISP and that's why I can't do it. Here are some more screenshots:

traceroute google.com
traceroute to google.com (, 30 hops max, 60 byte packets
 1 (  1.729 ms  2.158 ms  2.158 ms
 2 (  5.662 ms  5.666 ms  5.661 ms
 3 (  13.786 ms  13.878 ms  13.882 ms
 4  * * *
 5 (  18.940 ms  18.950 ms  27.285 ms
 6 (  27.300 ms  18.450 ms  14.992 ms
 7 (  14.160 ms  14.177 ms  14.150 ms
 8 (  13.478 ms  13.499 ms  13.487 ms
 9  bom07s01-in-f14.1e100.net (  13.458 ms  13.685 ms  13.649 ms

the following shows nmap on immediate hop:


Starting Nmap 7.01 ( https://nmap.org ) at 2016-11-22 10:35 IST
Nmap scan report for
Host is up (0.0073s latency).
Not shown: 997 closed ports
23/tcp   open  telnet
2000/tcp open  cisco-sccp
8291/tcp open  unknown

Nmap done: 1 IP address (1 host up) scanned in 16.01 seconds
  • can't add more screenshots, need more reputation points Nov 22, 2016 at 5:46
  • Unfortunately, questions about home networking and consumer-grade devices are explicitly off-topic here. You could try to ask this question on Super User.
    – Ron Maupin
    Nov 22, 2016 at 15:50

1 Answer 1


You are correct, you're ISP is using an additional box to NAT your connection. They are doing this to conserve IPv4 addresses, and it's called Carrier Grade NAT (CGN). This makes it impossible for you to use port-forwards unless your ISP also configures them on their CGN-box (which they will probably refuse to do).

CGN should only be used as a transition mechanism in combination with IPv6. With IPv6 you can have as many public IPs in your network as you need. If your provider is currently not giving you IPv6 addresses, then you should definitely complain about being behind CGN.

As an aside: the IP range that you ISP (Syscon?) is using to NAT your connection ( is indeed a public IP range, but one that does not belong to them and is in use by AOL. If you're having trouble gaming or making Skype calls to the US, that is probably why.

  • is it possible to make my computer public given these circumstances and the fact that my ISP will not entertain my request? Nov 22, 2016 at 9:24
  • If you want a public address, your ISP will be happy to give you one, for an additional cost I assume. Asking us to help you circumvent restrictions like this is off-topic here.
    – Ron Trunk
    Nov 22, 2016 at 12:31

Not the answer you're looking for? Browse other questions tagged or ask your own question.