I use an ASUS Router RT66 in connection with a synology station, where webdav is running.
All is configured and if I connect from outside, over the internet, all works fine.
I use https with port 5006. If i try to connect with my mobile inside the own network, it does not work. I will be asked for a password, but this will  not be accept.
At home I use the the same configuration with the synology station. It works fine over internet and in the local network. The only difference is the router.  Could it be a DNS issue?
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nociSoftware EngineerCommented:
If you use  HTTPS then the certificate is verified, and it internal name might not be the same as the external name (unless both are on the certificate).
So not a DNS issue per se, more an issue of naming, or...

Does the RT66 allow packets from the inside to the natted external address?

Before checking with high end tools you may want to see what the response is using lower level tools...
curl -v https://example.com/

Username and passwork can be supplied with -k.
and check the returned info from curl for errors.

curl can be gotten from a repository or from https://curl.haxx.se/

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HEINZ_W_SUEESSAuthor Commented:
thanks, I will give your suggestions a try
many routers won't allow connecting to a WAN ip adress from the LAN.

this is either due to lack of nat reflexion feature, or antispoof policies.

try connecting to the LAN IP address of the synology NAS
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HEINZ_W_SUEESSAuthor Commented:
thanks, maybe I have to change the router ...
there is no point in changing the router. the router may not be your problem. and there are other ways to circumvent the issue.

help us corner the issue by providing debug information : do you use the ip address or a dns name ? do you reach the synology at all ? you can test using telnet / netcat or better "openssl s_client host:port"

if the synology is reachable and rejects the password, this is a whole different issue.
HEINZ_W_SUEESSAuthor Commented:
thanks I will try it
Prabhin MPDevOps EngineerCommented:
make sure that you have proper SSL certificate installed.
from LAN how are you accessing? using IP?

System triggers an error when you are accessing from internal with  IP address. and SSL hostname  doesnt match with how you are accesing
better to create a local DNS record,  as in SSL certificates
HEINZ_W_SUEESSAuthor Commented:
HEINZ_W_SUEESSAuthor Commented:
For webdav I use into the LAN the same url as from outsise: https://nas.diekinderphysiotherapie.ch:5006
If I use inside the LAN the local IP-Adress it also works
HEINZ_W_SUEESSAuthor Commented:
thanks to all, now it works!
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