If you are experiencing really slow web browsing but downloads seem to be at normal speed, you may be a victim of a DNS (domain name service) cache poisoning attack. This can affect any operating system connected to the Internet. Many of my professional clients have been impacted by this recently. It is becoming a common issue. The simple test to see if you are being impacted is to download a file from a known source such as Microsoft or Apple. If the download proceeds normal speed, but web browsing is slow and sluggish, you may be affected.
On windows based systems:
Open a command prompt and type in “ipconfig /flushdns” without the quotes. Press enter. To prevent future issues you can disable the DNS client service in the Admin Tools–> Services section.
On Mac systems:
Leopard and newer
Open a bsh shell prompt and type in “dnscacheutil -flushdns” without the quotes.
Earlier than 10.5.2
Open a bsh shell prompt and type in “lookupd -flushcache” without the quotes.
On Nix systems:
From a console with root priveledges “/etc/init.d/nscd.restart” without the quotes. G/K/Ubuntu users “su /etc/init.d/nscd.restart” without the quotes.
Most security programs have no mechanism to prevent this from occurring. I do recommend ESET’s Smart Security Suite for Windows. It will prevent this issue.