I'm not sure about split-horizon DNS, frankly I think that is a different bug entirely. However, I have had no problems with DNS leaks over my VPN connections whatsoever on Ubuntu 17.10. The bugfix I personally requested from the NM-devs and backported to Ubuntu 17.04 (running NetworkManager v1.4.x) was effectively just patching the negative dns-priority bug related to systemd-resolved. From 'man nm- settings': "Negative values have the special effect of excluding other configurations with a greater priority value; so in presence of at least a negative priority, only DNS servers from connections with the lowest priority value will be used." This means that DNS servers configured for the non-VPN connection will be 'unseated' and ONLY the VPN-configured DNS servers are used.
Ubuntu 17.10 is running NetworkManager v1.8.4, so Thomas Haller's merged bugfix is present and working. You MUST use the command: 'sudo nmcli connection modify <vpn-connection-name> ipv4.dns-priority -42' or similar to actually set negative DNS priority for the VPN connection. Restart the network manager with 'sudo service network-manager restart', then connect to the VPN. Examine the output of 'systemd-resolved --status' and use the 'Extended' test on dnsleaktest.com to verify that you are not leaking DNS queries. I use openvpn, but setting negative dns priority should work for preventing DNS leaks over regular VPN connections of all kinds as a kind of 'catch-all'. Auto-connecting to openvpn through the GUI is a little troublesome in 17.10, but this 'fix' worked for me: https://askubuntu.com/questions/967408/how-to-automatically-connect-to-vpn-in-ubuntu-17-10/967415#967415 -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to network-manager in Ubuntu. https://bugs.launchpad.net/bugs/1624317 Title: systemd-resolved breaks VPN with split-horizon DNS Status in NetworkManager: Unknown Status in network-manager package in Ubuntu: Confirmed Status in network-manager source package in Zesty: Confirmed Status in network-manager source package in Artful: Confirmed Bug description: [Impact] * NetworkManager incorrectly handles dns-priority of the VPN-like connections, which leads to leaking DNS queries outside of the VPN into the general internet. * Upstream has resolved this issue in master and 1.8 to correctly configure any dns backends with negative dns-priority settings. [Test Case] #FIXME# * detailed instructions how to reproduce the bug * these should allow someone who is not familiar with the affected package to reproduce the bug and verify that the updated package fixes the problem. #FIXME# [Regression Potential] * If this issue is changed DNS resolution will change, for certain queries, to go via VPN rather than general internet. And therefore, one may get new/different results or even loose access to resolve/access certain parts of the interent depending on what the DNS server on VPN chooses to respond to. [Other Info] * Original bug report I use a VPN configured with network-manager-openconnect-gnome in which a split-horizon DNS setup assigns different addresses to some names inside the remote network than the addresses seen for those names from outside the remote network. However, systemd-resolved often decides to ignore the VPN’s DNS servers and use the local network’s DNS servers to resolve names (whether in the remote domain or not), breaking the split-horizon DNS. This related bug, reported by Lennart Poettering himself, was closed with the current Fedora release at the time reaching EOL: https://bugzilla.redhat.com/show_bug.cgi?id=1151544 To manage notifications about this bug go to: https://bugs.launchpad.net/network-manager/+bug/1624317/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
