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I want to connect to a WAN dynamic IP without DDNS, due to my router having problems when using DDNS. Is this possible and how do I do so?

  • I want to host a Minecraft server and let somebody else join
  • I know both the WAN IP and the target machine's IP within the LAN [192.168.1.55]

EDIT: Set up a web server behind a Carrier Grade NAT solved my problem.

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    Just have them connect to the external IP address? If you have port forwarding set up, it should work. DDNS is just to translate from a name (myserver.ddns.org) to an IP address, which is what the computer would do anyway. – mtak Jan 11 '22 at 12:58
  • No, my router's port forwording does not work for some weird reason @mtak –  Jan 11 '22 at 12:59
  • **@mtak:** Your comment is factually inaccurate - the purpose of DDNS is to supply a hostname to a dynamic [non-static] WAN IP. **00001H:** You can access any WAN IP without DDNS, however without a static WAN IP, the connection will be unstable over time since the WAN IP will be changed by the ISP, sometimes daily, perhaps in weeks/months, but it will change. When it does change, you'll need to provide the new WAN IP, which becomes an inconvenient hassle, hence DDNS _(please don't post WAN IPs in questions/answer, anonymizing them prior to posting)_ – JW0914 Jan 11 '22 at 13:26
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    If port forwarding dosen't work - DDNS isn't helpful. I have ddns but need to open ports as needed to get access to internal resources inside my lan anyway. Its two different problems - finding your external IP and actually connecting in – Journeyman Geek Jan 11 '22 at 13:34
  • @00001H If your router has an issue with DDNS and NAT, they're likely a symptom of the same issue, incl. if your ISP employs CNAT [carrier NAT] - backup your router config and flash the most up-to-date firmware image from the OEM's site. If the issue still exists after the firmware flash, reset the router to default and configure DDNS and DNAT [port forward], as the issue will either be related to CNAT, the config related, or the firmware and it's unlikely it's the latter since the entire purpose of a router than differentiates it from a switch is NAT and it's stateful firewall. – JW0914 Jan 11 '22 at 13:34
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    If your port forwarding does not work, you have a different problem. In your router's web interface, note the WAN IP address it reports. When you go to an IP check website (any will do), does it report the same IP address? – Daniel B Jan 11 '22 at 13:34
  • You could factory-reset the router if its firmware is malfunctioning. – harrymc Jan 11 '22 at 13:37
  • @DanielB The addresses are different. –  Jan 11 '22 at 13:39
  • @harrymc Tried that, and that did nothing other than breaking the router and requiring the ISP's repairman to come and fix it –  Jan 11 '22 at 13:40
  • Actually, changing anything that is mentioned in guides either completely disables network access or does nothing –  Jan 11 '22 at 13:41
  • I'm not impressed with that router. You should ask the ISP Support to fix port-forwarding, or ask for another model router, or change ISP. – harrymc Jan 11 '22 at 13:42
  • @00001H Please see my prior comment for how to troubleshoot and determine what's the issue, as it's either a bad/misconfigured config, corruption in the OEM firmware, or carrier NAT - it can literally only be one of those three things – JW0914 Jan 11 '22 at 13:43
  • @JW0914 1. I will be notified when you comment no need to @ me 2. Not a bad config Totally also 2. Not a corruption in firmware Totally 4. IDK What is a carrier NAT(I am a game developer, not a network expert, okay?) –  Jan 11 '22 at 13:46
  • Also there are no firmware flashing options or any firmware downloads of any sort –  Jan 11 '22 at 13:47
  • Actually I think the ISP does not want the user to configure anything(like port forwarding) so they make them either useless or let them remove internet access According to some forum: The port forwarding option is there, but it does nothing EDIT(@JW0914): I have only 1 rep I can't make chat and comments have an edit timer. Once I edited a comment so much I used up the 5 minutes writing edits –  Jan 11 '22 at 13:47
  • @00001H It can only be one of those three things as DDNS and NAT are done via software within the firmware and carrier NAT doesn't use the WAN IP you previously posted _(please don't post comment after comment, instead, please edit your comments, as this isn't a chat)_; because this is software-based, it can't be hardware-related if you're able to access the internet since, by default, that means NAT and the stateful firewall work. – JW0914 Jan 11 '22 at 13:48

2 Answers2

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You indicate that the public IP address that websites report and the WAN IP address your router reports are different. This means you are behind carrier-grade NAT. You will not be able to receive incoming connections with this type of internet connection.

As indicated in the Wikipedia article, you can also infer this by looking at the WAN IP your router reports. If it is in one of the following ranges, you are affected:

  • 10.0.0.0/8 (10.0.0.0 to 10.255.255.255)
  • 100.64.0.0/10 (100.64.0.0 to 100.127.255.255)
  • 172.16.0.0/12 (172.16.0.0 to 172.31.255.255)
  • 192.168.0.0/16 (192.168.0.0 to 192.168.255.255)

However, there is no guarantee that other WAN IP addresses are "safe", the ISP could decide to use whatever address range here. Testing the reported and actual public IP address is the safest way to check.

It doesn't hurt to ask your ISP whether the connection type could be switched.

Daniel B
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  • Can it be CGNAT when the WAN IP [begins](https://superuser.com/posts/1698639/revisions) with `212`? – JW0914 Jan 11 '22 at 13:55
  • @JW0914 Sure, why not? Unfortunately we do not know whether this is the WAN IP as reported by the router or the public IP address as reported by one of the websites for that. – Daniel B Jan 11 '22 at 14:04
  • If it's router-reported, then it's unlikely to be CGNAT, as assigning global IP addresses to CGNAT hosts kinda defeats the purpose of CGNAT... but on the other hand, it could _easily_ be behind an ISP-level firewall that blocks inbound connections "because it's not a business plan", regardless of CGNAT or not. Wouldn't be the ISP to do so. – u1686_grawity Jan 12 '22 at 14:47
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First things first, there are some troubleshooting steps needed.

  1. try to ping to your DDNS domain from your router configurations itself under Maintenance > Diagnostics > Ping Test (or whatever steps in your router gateway), as I experienced same issue before as the ping test fails due to DNS issue as the router couldn't resolve server name.

  2. Check firewall settings and in some cases DDNS feature doesn't work if DHCP server disabled if the router in AP mode.

  3. latest reason is that your router uses old protocol to comunicate with the DDNS service provider that they already updated as example dynu.com uses latest version of GNUdip protocol for security reasons and your router uses an outdated version.

But if you insist to use DDNS feature from your router itself without any addtional device running client software you may need to test DDNS-over-CWMP it uses Google Script as ACS endpoint and it can update update IP changes to DuckDNS.org once the router powered on, rebooted and periodically in seconds this is actually any DDNS client do and tested with 12 years old routers and it works as expected.

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Finally you can use tunneling services like that

Mamdouh Saeed
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