ubuntu@ubuntu:~$ sudo apt install bcmwl-kernel-source 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following extra packages will be installed:
  dkms
The following NEW packages will be installed:
  bcmwl-kernel-source dkms
0 upgraded, 2 newly installed, 0 to remove and 1 not upgraded.
Need to get 1,510 kB/1,576 kB of archives.
After this operation, 8,363 kB of additional disk space will be used.
Do you want to continue? [Y/n] Y
Err http://archive.ubuntu.com/ubuntu/ wily/restricted bcmwl-kernel-source amd64 6.30.223.248+bdcom-0ubuntu5
  Temporary failure resolving 'archive.ubuntu.com'
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/restricted/b/bcmwl/bcmwl-kernel-source_6.30.223.248+bdcom-0ubuntu5_amd64.deb  Temporary failure resolving 'archive.ubuntu.com'

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?