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After a lot of problems and hours of analyze we have recognized a bad error in DynDNS. Lets start with a domain "mydomain.dyndns.org". We have a router that send its ip-address regulary to http://dyndns.org. We can track this in the update host log. All is fine. Now we go to an other PC on an other place, we call it "outside-PC". This outside-PC gets a different ip-address from the provider as expected. We just sign into http://dyndns.org, we do nothing else, only sing in. But http://dyndns.org changes the ip-address of http://mydomain.dyndns.org to the ip-address of the outside-PC that did the sign in. To make it clear: we do not use the function to set the ip-address! After this login http://mydomain.dyndns.org is unreachable due to the wrong ip-address. The second error case is much worse. We wondered why we always get the ip-address of the PC that issued the nslookup command and never the current ip-address of http://mydomain.dyndns.org. Now we know why. If you call on an outside-PC the winsock function like "gethostbyname" to retrieve the current ip-address of the router, dyndns replaces the current ip-address of http://mydomain.dyndns.org with the ip-address of the outside-PC and returns this ip-address as current ip-address of the domain. After this call http://mydomain.dyndns.org is unreachable due to the wrong ip-address. |
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The only way that can happen is if you have an update client installed on outside-PC. Simply doing lookup cannot cause this to happen.
I appreciate that seems to be what you're seeing, but it isn't the case. I regularly sign in to my account from outside of my home network but nothing is updated. Doing a lookup of my hostname from other locations doesn't change the IP address either. There are only 2 ways of changing the IP address, as it is recorded at DynDNS:
The behaviour you are seeing can only be caused by one of those. If it was what you think you're seeing then a massive number of people would be reporting the same problem. |
Fine, try with mine: Edit: |
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No, we have not installed an update client on outside-PC. Our test results on the outside-PC are: nslookup http://mydomain.dyndns.org -> no change of the current ip-address ping http://mydomain.dyndns.org -> no change of the current ip-address php: gethostbyname("mydomain.dyndns.org") -> no change of the current ip-address wsock32: gethostbyname("mydomain.dyndns.org") -> change of the current ip-address http: sign in to the account "mydomain.dyndns.org" -> change of the current ip-address I guess that I can destroy the current ip-address of every dyndns-domain by using wsock32: gethostbyname("mydomain.dyndns.org"). |