Установка постфикса - проблем с Кв. - добирается

Я должен установить постфикс для отправки автоматических писем от терминала человечности. Я попробовал этой командой:

sudo apt-get install postfix

Но я получил следующие ошибки:

WARNING: The following packages cannot be authenticated!
postfix
Install these packages without verification? [y/N] y

Err http://us.archive.ubuntu.com/ubuntu/ trusty-updates/main postfix amd64 2.11.0-1ubuntu1   Could not resolve 'us.archive.ubuntu.com' E: Failed to fetch http://us.archive.ubuntu.com/ubuntu/pool/main/p/postfix/postfix_2.11.0-1ubuntu1_amd64.deb Could not resolve 'us.archive.ubuntu.com'

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

Я также работал:

склонные sudo - получают обновление

и я получил это:

Err http://extras.ubuntu.com trusty InRelease    
Err http://security.ubuntu.com trusty-security InRelease
Err http://security.ubuntu.com trusty-security Release.gpg
Could not resolve 'security.ubuntu.com'
Err http://extras.ubuntu.com trusty Release.gpg
Could not resolve 'extras.ubuntu.com'
Err http://us.archive.ubuntu.com trusty InRelease
Err http://us.archive.ubuntu.com trusty-updates InRelease
Err http://us.archive.ubuntu.com trusty-backports InRelease
Err http://us.archive.ubuntu.com trusty Release.gpg
Could not resolve 'us.archive.ubuntu.com'
Err http://us.archive.ubuntu.com trusty-updates Release.gpg
Could not resolve 'us.archive.ubuntu.com'
Err http://us.archive.ubuntu.com trusty-backports Release.gpg
Could not resolve 'us.archive.ubuntu.com'
Reading package lists... Done
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty/InRelease  
W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/InRelease  

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-backports/InRelease  

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/InRelease  

W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/trusty/InRelease  

W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/trusty/Release.gpg  Could not resolve 'extras.ubuntu.com'

W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/Release.gpg   Could not resolve 'security.ubuntu.com'

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty/Release.gpg  Could not resolve 'us.archive.ubuntu.com'

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-updates/Release.gpg   Could not resolve 'us.archive.ubuntu.com'

W: Failed to fetch http://us.archive.ubuntu.com/ubuntu/dists/trusty-backports/Release.gpg Could not resolve 'us.archive.ubuntu.com'

W: Some index files failed to download. They have been ignored, or old ones used instead.

Заранее спасибо

P.S.: Моя версия человечности 14.04LTS, и я выполняю ее Плеером VMware Workstation 12.