UPDATED: Specific Name Server Entry in /etc/resolv.conf File May Cause Networking Issues

Elizabeth -

Due to a change made by one of our network providers, we have identified an issue with an entry that may exist in the /etc/resolv.conf file of your instance(s) -- an entry which specifies a name server that no longer works. To prevent potential networking issues, we suggest that you check your /etc/resolv.conf file for the following entry:


If the above entry exists, please remove it or comment it out. Going forward, this issue will not be seen on newly-provisioned instances.

NEW UPDATE (as of 8-Sept-2015):

Some Docker containers and infrastructure containers have been identified as having this bad DNS entry, which may cause unexpected network delays. 

Manually Updating Docker Containers:

To manually check whether your Docker containers have the bad DNS resolver entry and fix them as needed, please follow the steps below:

1 - Start up a shell to your container:

$ docker exec -i -t [container_id] /bin/bash

2 - Check the resolv.conf file:

root@a4558f78acb0:/# cat /etc/resolv.conf

3 - If the bad DNS entry exists (, you can update it as follows:

a - Add good entries to a test file:

root@a4558f78acb0:/# echo "nameserver" > test

root@a4558f78acb0:/# echo "namserver">>test

b - Verify the contents of the test file:

root@a4558f78acb0:/# cat test

c - Back up your resolv.conf file:

root@a4558f78acb0:/# mv /etc/resolv.conf /etc/resolv.conf.orig

d - Move the test file to /etc/resolv.conf:

root@a4558f78acb0:/# mv test /etc/resolv.conf

e - Verify that the contents have been updated:

root@a4558f78acb0:/# cat /etc/resolv.conf

Manually Updating Infrastructure Containers:

To manually check whether your infrastructure containers have the bad DNS resolver entry and fix them as needed, please follow the steps below:

1 - Log in to your container and check the /etc/resolv.conf file.

2 - If the entry exists, remove it or comment it out.


Manually Updating KVM Linux VMs:

  1. Create an executable file called /etc/dhclient-enter-hooks and redefine the function responsible for auto-populating that: 
    # Used to keep resolv.conf w/o changing
    # just need to redefine the function 
    make_resolv_conf() { 


  2. Adjust /etc/resolv.conf to your desired configuration: 
    # cat > /etc/resolv.conf << !
  3. Reboot
  4. Validate that your changes are in place: 
    # cat /etc/resolv.conf


If you have any further questions or concerns, please contact our Support team by raising a ticket at https://help.joyent.com or by email to support@joyent.com.

Have more questions? Submit a request


Article is closed for comments.