• Firewall

    A network firewall is a device placed between networks of different trust levels to filter authorized and unauthorized packets.

    This is done by sequentially checking a packet against a set of rules until one that matches the packet is found.

  • Rule Set

    A set of rules for filtering packets configured on the firewall. These are derived from the security policy of the organisation.

    Each rule specifies the action to be applied to the packet - ALLOW or DENY entry into the network.

  • Optimization

    Sequential evaluation of rule sets to find a matching rule for the packet reduces matching time; negative impact on filtering performance.

    Reducing the inspection time by applying less rules to packets is one solution investigated in this research.

To the most high God, Jah , king of kings, Lord of Lords, maker of heaven and earth who gave me life and blessed me with so much, praise be to thee whose wisdom endures forever !

I am very grateful to my supervisor, Mr Barry Irwin, whose involvement in this work and experience in the field of Information Security I have been privileged to learn a lot from, Barry thank you very much for your guidance and being instrumental in seeing this work come to completion. Thank you to the members of the Security and Networks Research Group (SNRG) at Rhodes University for their sharing and teaching spirit.

I am grateful to my parents, Mr Katandula W Mukupa and Mrs Elizabeth Chewe Mukupa for their love and support. To my beautiful mum "ba nakulu Sapwe", sweet smile and eyes like mine, thank you for your teachings and instructions that have shaped me into this man I am today. To my father, who always told me to work hard towards what I believed in and seek excellence, thank you very much. Thanks to all my brothers and sisters who have been so supportive and keep standing with me through out. I love you all.

I am thanking my brother Prudential Chongo Mukupa who never hesitated to put my life and growth in his hands. Your lessons, love and financial commitment to my progress and pursuance of my independence has been heavenly.

It takes a certain type of man or woman to teach another something that will make them better. Living in this world is a challenge in itself and I have been able to grow and breakthrough those challenges thanks to the teachings of men and women labouring for the advancement of God's kingdom; Bishop Roy Wallace and other pastors of the Gospel Outreach Church in Hochland Park, Windhoek, Namibia. My humble thanks to Rev. Helmut Reutter, Pastors Jeff Musonda, Dickson Phiri, Mbinda Wina and other ministers of God's word at the Gospel Outreach Fellowship Centre in Lusaka Zambia , for their life equipping gospel teachings that have taught me a lot and shaped me this far.

I wish to extend my thanks to River of Life Church in Grahamstown and Pastors John and Debbie Sloane in particular for their encouragement and spiritual feeding without which, my life in Grahamstown would have been empty.

What would one be without friends? I wish to thank the Nawas, Elleanor and Watae for the encouragement and care showed to me always. Mwape Mo Chileshe, you keep a positive heart going when you crack jokes in moments of reflection. To Namulya Mung'omba, Malama, Sydney, Ndalameta, Benard, Alfred, Jasmine, Biko, Zirimah, K.T.L Pohamba,Vasti, Nimrod , Lahya, Vicentius aka Viddo, Mao, JayBee, Katapa, Chipampa, Kanguma, Gavin, Scotch, Martinez, Clive, Feven, Mush-k, Mushani, Pingi, Kambole Banda,Koki Kojela, and to all of you friends that I have become family with.Thank you for your prayers, good wishes and help that made the load of life easy for me to carry - ONE BLOOD.

To Mpande Chizhyuka and Mabvuto Mumba, your running around for me made it possible to get to Rhodes. You cared and settled me well in Grahamstown. Your reward is from God who you served by doing that for one of his children. Thank you so much for being there for me.

I wish to acknowledge the support of the following cooperating partners of the department of computer science at Rhodes University; Telkom SA, Comverse SA, Stortech, Tellabs, Easttel, Bright Ideas Projects 39 and THRIP through the Telkom Centre of Excellence at Rhodes University. Their material provision made this work possible by providing a learning environment in which I have been able to utilize my potential as a student.