Weekly outgoing packets. The function of a firewall

Weekly Activity
Data security is the practice of
keeping the data protected from being corrupt and unauthorised access.
Whether using Facebook to chat with your friends, watching YouTube videos or
doing any important online work must be awared by users. Data security is the practice of
keeping your data protected from being corrupt and unauthorised access.
Whether you are using Facebook to chat with your friends, watching YouTube
videos, or doing any important online work you must be aware of data security.
Measures that can be taken to keep data secure include:
   -Making
regular backups of files (backup copies should be stored in
fireproof safes or in another building)
   -Protecting
yourself against viruses by running anti-virus software
   -Using a
system of passwords so that access to data is restricted
   -Safe
storage of important files stored on removable disks, eg locked away in
a fireproof and waterproof safe
   -Allowing
only authorised staff into certain computer areas, eg by controlling entry to
these areas by means of  ID cards or
magnetic swipe cards
  -Always
logging off or turning terminals off and if possible locking them
  -Avoiding
accidental deletion of files by write-protecting disks
  -Using
data encryption techniques to code data so that it makes no
apparent sense
One of the biggest contributions to ensuring data
security is the existence of the firewall.A firewall is a security guard
placed between a private network and the outside Internet that monitors all
incoming and outgoing packets. The function of a firewall is to examine every
packet and decide whether to accept or discard it based upon the firewall’s
policy. This policy is specified as a sequence of (possibly conflicting)
rules. When a packet comes to a firewall, the firewall searches for the first
rule that the packet matches, and executes the decision of that rule.With the
explosive growth of Internet-based applications and malicious attacks, the
number of rules in firewalls have been increasing rapidly, which consequently
degrades network performance and throughput. In this paper, we propose
Firewall Compressor, a framework that can significantly reduce the number of
rules in a firewall while keeping the semantics of the firewall unchanged.We
make three major contributions in this paper. First,we propose an optimal
solution using dynamic programming techniques for compressing one-dimensional
firewalls. Second, we present a systematic approach to compressing
multi-dimensional firewalls. Last, we conducted extensive experiments to
evaluate Firewall Compressor. In terms of effectiveness, Firewall Compressor
achieves an average compression ratio of 52.3% on reallife rule sets. In
terms of efficiency, Firewall Compressor runs in seconds even for a large
firewall with thousands of rules.
Moreover, the algorithms and techniques proposed in
this paper are not limited to firewalls. Rather, they can be applied to other
rule-based systems such as packet filters on Internet routers.