Along with the advantages, firewalls also has some disadvantages, these disadvantages will indicate that firewalls cannot alone provide good security for the networks. The disadvantages are:
  • Intruders can easily make attacks by focusing on the firewalls they consider firewalls as the focal points for making some malicious activity. If once the intruder is able to break through the firewall then he can access the network of any corporate organization without having any restrictions.
  • Sometimes even the authorized users may face some problems using these firewalls because they may be interrupted in accessing the services provided by their organization. For example, if the users are away from the work place or if they are working from home then they are restricted to access the corporate network.
  • Firewalls also fail to protect the corporate networks from the back door attacks. Firewalls cannot interrupt the users entering or exiting through the back doors, and this is caused when the service interruptions are more enough. The users can enter into the corporate networks by the entrances like exporting and importing of floppy discs, by modems. There is a necessity for the security policies to cover all these factors also.
  • As all the connections in the network pass through the firewall system and so firewalls behave as bottlenecks for the throughput.
  • The intruder activities like smuggling cannot be interrupted by the firewall systems. Therefore the network cannot be protected by the firewalls. Firewalls can also export and import some material that is banned for example, material attached to the mails and the other games and programmes. If the users had download softwarefrom the outer official statement boards then there is a chance of smuggling in terms of some virus which can be considered as very important. Firewalls cannot avoid the viruses that are passed from the attachments of the e-mails for example the Melissa and love bug are the viruses that are smuggled through emails without any notice of the recipient. Particularly in this type of situations better security policies are required. This type of issues can be addressed using some software packages that are specially designed for identifying the viruses that are passed from the attachments of e-mails and they are scanned before they are downloaded. These software packages can remove the viruses that cause damage for the networks and systems.
  • Firewalls cannot protect the attacks caused by the inside attackers and this considered as the main disadvantage of firewalls. It’s a fact that most of the crimes in corporate companies are caused by the internal users of the company in this case firewalls are used to provide a little security but not a high level security. The internal users can send the sensitive information of the organization to other attackers using the email approach or bye copying those files into some floppy discs and then export them to intruders. So more concentration should be paid on firewalls in order to develop them in such a way that they can address all these disadvantages.