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JorgeeFG
Asked: 2017-05-15 20:20:43 +0800 CST

Connection info shows correct DNS but resolvconf does not show the same

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The problem:

My DNS is getting hijacked by my ISP, when I enter a webpage, sometimes it redirects me to "Download Bill" page.

I've tried to see why this happens, then I found something else. I have DD-WRT in my router, with DNSMASQ for DHCP and DNS, with fixed DNS IPs (Open DNS).

But in Ubuntu, my resolv.conf shows it is using 127.0.0.1 (and so does nslookup), so not querying the router? But then Connection Info shows the right information.

What is wrong here?

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networking

2 Answers

  1. NetworkManager is the program which (via the resolvconf utility) inserts address 127.0.1.1 into resolv.conf. NM inserts that address if an only if it is configured to start an instance of the dnsmasq program to serve as a local forwarding nameserver. That dnsmasq instance listens for queries at address 127.0.1.1.

    If you wish to see witch DNS you use currently type command

    nmcli device show <interfacename> | grep IP4.DNS

    You can set different DNS param for each connection

    If you do not want to use a local forwarding nameserver then configure NetworkManager not to start a dnsmasq instance and not to insert that address. In /etc/NetworkManager/NetworkManager.conf comment out the line dns=dnsmasq

    sudo nano /etc/NetworkManager/NetworkManager.conf

[main]
plugins=ifupdown,keyfile,ofono
#dns=dnsmasq

    and restart the NetworkManager service.

    sudo service network-manager restart

    In this mode, NetworkManager updates /etc/resolv.conf (still via resolvconf) to include the nameserver addresses NetworkManager has for active connections.

    If you want to disable the resolvconf mechanism for updating resolv.conf and just use a static resolv.conf file, do the following.

    sudo rm -f /etc/resolv.conf  # Delete the symbolic link
sudo nano /etc/resolv.conf   # Create static file

# Content of static resolv.conf
nameserver 8.8.4.4
nameserver 8.8.8.8
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  2. dnsmasq is a good thing; I wouldn't disable it: https://help.ubuntu.com/community/Dnsmasq

    A local DNS cache can speed up internet browsing because the user's browser will not need to access a domain name server when it looks up a domain name the computer has visited before.

    On the other hand, if the DNS nameserver that is provided by your ISP is getting hijacked, then, by all means, don't use it! You may specify alternate DNS nameservers in Network Manager like this:

    enter image description here

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