I have an apache webserver / mailserver (running on Ubuntu) setup like following:
- Speedport Router with NAT for all required ports
- DynDNS to get the domain name by using a non-static IP address
The problem I face is, that the website abc.com can be accessed ok from outside of the Intranet but not anymore from the inside.
The speedport router does not allow to make any changes regarding to the domain name routing
This is my hosts file:
127.0.0.1 localhost localhost.localdomain 127.0.0.1 localhost #192.168.2.110 marvin.localhost.com marvin #10.8.0.1 marvin marvin.localhost.com 127.0.0.1 mx.localhost.com.cust.b.hostedemail.com 192.168.2.110 DOMAINNAME.com # 192.168.2.110 marvin.DOMAINNAME.com marvin ::1 localhost ip6-localhost ip6-loopback fe00::0 ip6-localnet ff00::0 ip6-mcastprefix ff02::1 ip6-allnodes ff02::2 ip6-allrouters
This used to work ok for a year and suddenly stopped working, which puzzles me.
It seems like in the Intranet the domainname is not published / routed correctly.
This is a side effect of using NAT with IPv4. Your intranet clients get the “outside” IP address, but that address is only accessible from outside the intranet.
There are two solutions: The first is split-horizon DNS. The second (and probably much better) solution is to deploy IPv6, which does not suffer from this problem.
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