This is important for many applications, such as a browser when it tries to connect to a server with many IP addresses for the same hostname (DNS round robin). The main characteristic of the outbound policy is that the client only receives an ACK when the requested server is really up. This example shows how the outbound and inbound accept policies handle TCP connections and which policy to use: Outgoing TCP Connection with Outbound Accept Policy Enabled TCP SYN Flooding Attacks and Countermeasures These settings are also configured on a per-rule basis. Number of Sessions per Source) to protect against resource exhaustion of the Barracuda CloudGen Firewall.
To guard against DoS/DDoS attacks, configure the maximum number of new sessions and the allowed total number of sessions from a single source ( Max. Only after a complete TCP handshake is established, the handshake with the target is processed and traffic will be forwarded to the target address. The firewall rather establishes a complete TCP handshake with the requesting source first, assuring that the requestor is authentic (no IP spoofing) and really intends to establish a TCP session. TCP session requests (SYN packets) are NOT immediately forwarded to the target address even if the session is allowed by the rule set. Inbound Accept Policy – Use the inbound accept policy to protect servers against untrusted networks.The TCP handshake occurs between the source and destination. TCP session requests (SYN packets) are immediately forwarded to the target address if the session is allowed by the rule set. Outbound Accept Policy – Use the outbound accept policy when trusted clients access untrusted networks.Depending on the purpose of the firewall rule, choose one of the two TCP accept policies: You can use different accept policies to change how incoming and outgoing TCP connections are handled on a per-rule basis. In order to establish a TCP connection, the TCP three-way handshake must be completed.
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