I can confirm this and reopend my Ticket #271547 accordingly, too.
So if a default gateway is set through dhcp it get replaced by openvpn (started via init script) but not by network-manager-openvpn.
For DNS there is also another Bugreport, that I created: #271542 for network-manager
In my case the DNS Server doesn't get set correctly, when connecting to the wifi network and getting the nameserver information from dhcp. However nameserver does get set correctly after nm-openvpn connected (after I added explicit DNS Options to the openvpn-server configuration, of course)
push "dhcp-option DNS <dnsserver>"
push "dhcp-option DOMAIN <domain>"
If the Openvpn Server does not provide DNS and DOMAIN the values of the undelaying connection should be used (which in my case were empty, so I had to add the dhcp-option mentioned above)
Like Tore I also noticed that "dhcp-option DOMAIN <domain>" is set as search domain
If you look at the Manpage of openvpn under "--dhcp-option type [parm]" you will not find an option SEARCH, there is only DOMAIN, and it seems DOMAIN is interpreted as SEARCH (there is no other option to set the search domains - SEARCH is more important than DOMAIN in my Opinion)
Tore, one more thing: I would like to know if you have resolvconf installed - I do.
For plain Openvpn look at the script /etc/openvpn/update-resolv-conf, /sbin/resolvconf is used to set the dns options in this script. And also note that you probably need to add a parameter "up <script> "and "down <script>" to your openvpn conf file.
I can confirm this and reopend my Ticket #271547 accordingly, too. manager- openvpn.
So if a default gateway is set through dhcp it get replaced by openvpn (started via init script) but not by network-
For DNS there is also another Bugreport, that I created: #271542 for network-manager
In my case the DNS Server doesn't get set correctly, when connecting to the wifi network and getting the nameserver information from dhcp. However nameserver does get set correctly after nm-openvpn connected (after I added explicit DNS Options to the openvpn-server configuration, of course)
push "dhcp-option DNS <dnsserver>"
push "dhcp-option DOMAIN <domain>"
If the Openvpn Server does not provide DNS and DOMAIN the values of the undelaying connection should be used (which in my case were empty, so I had to add the dhcp-option mentioned above)
Like Tore I also noticed that "dhcp-option DOMAIN <domain>" is set as search domain
If you look at the Manpage of openvpn under "--dhcp-option type [parm]" you will not find an option SEARCH, there is only DOMAIN, and it seems DOMAIN is interpreted as SEARCH (there is no other option to set the search domains - SEARCH is more important than DOMAIN in my Opinion)
Tore, one more thing: I would like to know if you have resolvconf installed - I do.
For plain Openvpn look at the script /etc/openvpn/ update- resolv- conf, /sbin/resolvconf is used to set the dns options in this script. And also note that you probably need to add a parameter "up <script> "and "down <script>" to your openvpn conf file.