Configuration issues can be responsible for problems accessing the internet through the Internet Explorer or Mozilla Firefox web browser. The LAN settings of the web browsers should be checked if the user is unable to access the web. The browser should be configured to automatically detect settings. Antivirus and firewall settings may also prevent access to the internet.The configuration settings for antivirus software and firewall settings must be checked to ensure that problems accessing the internet are not caused by improper settings. It must be noted that disabling the firewall or uninstalling the antivirus will make the system vulnerable to attacks.