Google has one of the best spam blockers in the business, and it's integrated into Google Apps. Spam is purged every 30 days. We have built in virus checking, and we enforce checking of documents before allowing a user to download any message. Most computer viruses are contained in executable files, so standard virus detectors scan messages for executable files that appear to be viruses. Google helps block viruses in the most direct possible way: by not allowing users to receive executable files (such as files ending in .exe) that could contain damaging executable code; even if they are sent in a compressed (.zip, .tar, .tgz, .taz, .z, .gz) format.
Google supplies Chrome™ and Firefox® users with constantly updated filters against phishing and malware. By combining advanced algorithms with reports about misleading pages from a number of sources, Google downloads to your browser a list of information about sites that may engage in phishing or contain malicious software. Safe Browsing is often able to automatically warn you when you encounter a page that's trying to trick you into disclosing personal information.
Google provides pieces of the spam-protection puzzle, from distributed computing to language detection. For example, they use optical character recognition (OCR) to protect Google Apps users from image spam. And machine-learning algorithms developed to merge and rank large sets of Google search results allowing them to combine hundreds of factors to classify spam.
There are three levels of Spam Filtering options available with Google Apps.
- Automated SPAM Protection - Google Apps has an automated system that helps detect spam by identifying viruses and suspicious messages, finding patterns across messages, and learning from what Gmail users like you commonly mark as spam. Google SPAM filters provides protection against Phishing scams, Message from unconfirmed Senders, Message you sent to Spam, similarity to suspicious message, message content is empty.
- Admin Level - Administrator can set policies for your domain users to mark email messages from particular sender, domain or IP address to consider it as SPAM. This policies could be imposed for predefined set of users or entire domain.
- User Level - Google Apps facilitates end user to allow any irrelevant messages to mark as SPAM. If you get an email in your inbox that is actually spam, you need to click the "Report Spam" to help Gmail to treat such messages as spam in the future.
