Network Security

Securing your data and infrastructure is a complex task that involves human engineering as well as hardware and software solutions. Although SIA is experienced with a wide variety of firewall and VPN products, our initial focus includes issues of employee access, rights and authentication.

After reviewing the security analysis that is included with our site surveys, SIA will advise you about the human factors involved in security. Many security breaches originate inside organizations. As Cisco puts it: “…employees, through mischief, malice, or mistake often manage to damage their own companies’ networks. Furthermore, remote partners and employees pose the same threats as internal employees, as well as the risk of security breaches if their remote networking assets are not properly secured and monitored.”

Another internal security issue involves Social Engineering where hackers get network security information (e.g. passwords) by calling employees and representing themselves as Help Desk personnel and simply asking the employees what their passwords are. Other examples are bribing employees for information or even searching offices for co- workers’ passwords.

Once you have determined your employee password and security policies, it is time to consider what type of firewall to install. Firewalls are hardware or software products that implement access control policies between your network and the outside world. Firewalls are designed to both block unacceptable inbound traffic and to permit desired outbound traffic. This means that the network administrator must determine which kinds of traffic to block and which types should be allowed. The administrator must also make sure that remote workers have desktop firewalls installed on their computers so that hackers cannot access company networks by “piggybacking” on the remote employee’s session. There are two main types of firewalls available (but keep in mind that some products combine both types into a single “appliance”):

  1. Stateful Inspection products from Cisco, Netscreen, WatchGuard, Check Point and others work by examining packets as they enter or leave the network. Both the IP addresses and the “context” of the packets are examined to see if they match the permissible criteria as configured by the network administrator. The context refers to the context of the user session e.g. if a user accesses an FTP server to download a file, the firewall monitors the entire process. It blocks non-FTP activity while keeping open the FTP firewall port until the download is complete. In this example, the firewall monitors client to server connections and only allows responses to permissible client requests.
  2. Application Proxy firewalls like those from Network Associates, Secure Computing Corp., WatchGuard, Symantec and others utilize proxy applications that mediate the communications between a client and a destination service. The proxy software protects the network computers by hiding them from the outside world. Incoming packets are inspected for content that violates security policies. Executable files, Java applets, ActiveX files and other potentially malicious code can be screened out. Proxies are usually configured for the standard types of Internet traffic like SMTP, FTP, and HTTP. Custom proxies can also be configured for individual applications and services (e.g. Real Audio).

Many firewalls also include Virtual Private Network (VPN) capabilities to allow branch offices and telecommuters to securely access the company network over phone lines or via the Internet. Security is typically ensured through the use of a tunneling protocol like IPSec and high level encryption – e.g. 168-bit 3DES.

For large enterprises, the ASIC based firewalls offer speeds up to 2Gbits/second and capacities up to 40,000 simultaneous connections. But for small to medium sized organizations, the all-in-one appliance type firewalls make the most sense. They often include VPNs and other useful features like bandwidth management, URL content filtering (to prevent employees from visiting undesirable sites) and Network Address Translation or NAT to hide your network from external threats. The appliance type firewalls like those from WatchGuard and SonicWall also simplify the task of security configuration and management.

Anti-Virus Products
The virus attacks of the past couple of years demonstrate the importance of installing and maintaining anti-virus software on your network servers and desktops. SIA can assist you with products from Symantec, McAfee and others. Many current products monitor your entire network and feature automatic upgrades over the Internet.

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