anthony

set proxyServer to "localhost"
set proxyPort to "30000"

tell application "System Preferences"
  activate
  set the current pane to pane id "com.apple.preference.network"
  get the name of every anchor of pane id "com.apple.preference.network"
  reveal anchor "Proxies" of pane id "com.apple.preference.network"
end tell

tell application "System Events"
  tell process "System Preferences"
    tell window "Network"
      tell sheet 1
        tell tab group 1
          tell group 1
            repeat with n from 1 to 3
              tell scroll area 1
                tell table 1
                  select row n
                  tell row n
                    click checkbox 1
                    set turnOnProxy to value of checkbox 1
                  end tell
                end tell
              end tell
              if turnOnProxy is 1 then
                tell group 1
                  set focused of text field 1 to true
                  set value of text field 1 to proxyPort
                  set focused of text field 2 to true
                  set value of text field 2 to proxyServer
                end tell
              end if
            end repeat
          end tell
        end tell
        click button "OK"
      end tell
      click button "Apply"
    end tell
  end tell
end tell

ignoring application responses
  tell application "System Preferences" to quit
end ignoring

if turnOnProxy is 1 then
  say "Proxies are set"
else
  say "Proxies are unset"
end if