vshpere wget: bad address 'releases.ubuntu.com'

Solution 1:

Assuming you have DNS set up correctly for ESXi, wget could be incorrectly preferring the IPv6 address for packages.ubuntu.com:

$ host releases.ubuntu.com
releases.ubuntu.com has address 91.189.92.151
releases.ubuntu.com has IPv6 address 2001:7b8:3:37::21:3

Try forcing IPv4 mode:

wget -4 http://releases.ubuntu.com/16.04/ubuntu-16.04-server-amd64.iso

EDIT:

Sorry, it seems the Busybox version of wget included with ESXi does not support the -4 flag, or any other way to force IPv4 vs. IPv6. Make sure you are at least getting some name resolution by trying to ping the site:

vmkping -c 3 releases.ubuntu.com

If this works but wget does not, you may need to download the ISO to an intermediate system, and then transfer it to your ESXi host.

Solution 2:

Login to the server with ssh and run this command to setup a DNS server:

esxcli network ip dns server add -s 8.8.8.8

Then simply run the "wget" command.

wget http://releases.ubuntu.com/16.04/ubuntu-16.04-server-amd64.iso

Thank you James Sneeringer for your lifesaver comment.