About Proxy Policies - Watchguard Firebox X15 User Manual

8
Proxy Settings

About proxy policies

All WatchGuard policies, whether they are packet filter policies or proxy policies, are important tools for
network security. While a packet filter examines each packet's IP and TCP/UDP header, a proxy monitors and
scans whole connections. It examines the commands used in the connection to make sure they are in the
correct syntax and order. It also uses deep packet inspection to make sure that connections are secure.
A proxy opens each packet in sequence, removes the network layer header, and examines the packet's
payload. It then puts the network information back on the packet and sends it to its destination. As a result, a
proxy can find forbidden content hidden or embedded in the data payload. For example, an SMTP proxy
examines all incoming SMTP packets (email) to find forbidden content, such as executable programs or files
written in scripting languages. Attackers frequently use these methods to send computer viruses. The SMTP
proxy can enforce a policy that forbids these content types, while a packet filter cannot detect the
unauthorized content in the packet's data payload.
If you have purchased and enabled additional security subscriptions (Gateway AntiVirus, Intrusion Prevention
Service, spamBlocker, WebBlocker), WatchGuard proxies can apply these services.
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