I have a DDNS domain registered and I can ssh it using my phone's internet connection. But when I try to access it from my home ISP, I am getting timeout error. I am using google's DNS at home.

Any ideas for some better DNS server or something else so I can connect from home network?


The issue is likely your gateway is not "properly" (matter of opinion) rewriting the source IP as it is NATing packets "out" to the external (DDNS) IP of your internal server. Sometimes this is called "hairpin NATing" or "loopback NAT", and this post offers a more complete explanation.

One solution (some might say work around) for this is split-horizon DNS for your internal network (lots of posts on this, including this one that might help). That is, instead of relying upon google's DNS, setup your own DNS server locally that offers different (internal) IP addresses for internal servers. That way, the traffic doesn't want to go out to the external address as registered via DDNS.

  • I tried with another ddns setup and I was able to ssh it. So ot seems this specific domain is causing me problems only from my home network. – CuriousGuy Apr 10 '17 at 18:01

If you perform an nslookup command on the fully qualified domain name from your home system, which is using Google's DNS server with IP address, does it return the appropriate IP address? E.g., nslookup myddns_address.example.com. I.e., do you get the right IP address, but can't establish an SSH connection to the system? I'm not sure from your post whether the timeout is for the SSH connection or an nslookup. If it is for the nslookup, can you look up the IP addresses for other systems from the home system. E.g., does nslookup superuser.com return an IP address? If you are, instead having issues with the SSH connection, though an nslookup returns the right IP address, do you know if the SSH server is restricting connections to particular IP addresses or ranges of addresses?

  • nslookup myddns.ddns.net Server: Address: Non-authoritative answer: Name: myddns.ddns.net Address: xx.xx.xx.xx It returns the IP. But even ssh with the IP results again in timeout – CuriousGuy Apr 8 '17 at 19:29

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