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My apologies if this has been asked before, but I can't seem to find a complete solution.

I have a hosted sub-domain at no-ip.com with a wildcard DNS option enabled. On my end I have a firewall port-forwarding TCP/UDP 53 to an internal server with Bind9 installed.

From inside the firewall everything resolves as expected, computer1.my.domain.net resolves to the correct IP. However, outside the firewall every DNS server says the same thing no matter what computer I try to reach.

Using https://toolbox.googleapps.com/apps/dig/

fossum.ddns.net

id 3263
opcode QUERY
rcode NOERROR
flags QR RD RA
;QUESTION
fossum.ddns.net. IN A
;ANSWER
fossum.ddns.net. 59 IN A 50.181.208.114
;AUTHORITY
;ADDITIONAL

mediaserver.fossum.ddns.net

id 22140
opcode QUERY
rcode NOERROR
flags QR RD RA
;QUESTION
mediaserver.fossum.ddns.net. IN A
;ANSWER
mediaserver.fossum.ddns.net. 59 IN A 50.181.208.114
;AUTHORITY
;ADDITIONAL

I don't even know where to start troubleshooting...

1

If you have two hosts behind the same NAT, they will resolve to the same IP address. There is no way around this; you only have one IP address and anyone coming from the outside needs to use this address.

If you want different traffic to go to your servers, you need to set port forwarding appropriately (for example port 80 to 192.168.1.2 and port 53 to 192.168.1.3). You set this in your router's NAT configuration. The only way I know to get connections to your NAT device to get routed to different local machines is to use different port numbers.

1
  • Dang. That's too bad. I wish that wasn't the case and it seems like that wouldn't be hard to fix... – Eric Fossum Dec 2 '15 at 21:26

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