Specifications

OmniAccess 5510 USG - Release Notes
September 2010
Denial-of-Service
A Denial-of-Service (DoS) attack is a malicious attempt by one or many users to limit or completely
disable the availability of a service. The OmniAccess 5510 USG provides an effective way to prevent
these attacks against their networks. The OmniAccess 5510 USG employs rate limiting and rule based
filtering to prevent these attacks.
Network Address Translation (NAT)
NAT mechanism translates un-registered "private" IP addresses used in an internal network to a real
"registered" IP on external networks such as the Internet. The OmniAccess 5510 USG supports three
types of NAT: Port Translation, Static NAT, and Dynamic NAT.
Application Layer Gateway
An ALG has the capability to conduct stringent packet inspection and thereby augment the security
infrastructure. Besides using a specialized program for each type of application or service that needs
to pass through the firewall, the OmniAccess 5510 USG can look for altered data, potentially harmful
traffic, data appropriateness, and also has the capability to log these. The OmniAccess 5510 USG can
perform ALG functions for the following protocols: TFTP, FTP, DNS, RTSP, and SIP ALG.
GRE
Generic Routing Encapsulation (GRE) is a simple, stateless protocol that allows for the tunneling of
traffic. IP is used as transport for GRE. GRE tunnels can be used to form VPNs, connecting remote
sites using private IP addresses via a public network. Typically, GRE tunnel is run between the
customer edge routers and are transparent to the rest of the network. GRE tunnels are used to carry
non-IP traffic (like IPX, Appletalk, DECnet from legacy networks) over an IP backbone.
Hosted SIP ALG
OmniAccess 5510 USG supports hosted SIP ALG with and without pin-holing. A mechanism where
the gateway (OmniAccess 5510 USG) does IP layer natting and SBC does ALG is referred as Hosted
SIP ALG (on the gateway side). The gateway must be able to open up pinholes for SIP session and
RTP session.
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