Bookmark  
   
 

Firewalls

Network Liquidators is your premier online destination for buying and selling firewalls. We keep an extensive inventory of firewalls in stock at most times which are usually available for overnight delivery. Along with our used firewalls, we also carry many other networking products including memory, gbics, interface cards, network modules, switches, cables, and chassis.

All of our firewalls go through a grueling inspection, testing, and refurbishing process and all of our firewalls comes standard with our Lifetime Warranty (end-user customers only). For details about our inspection, testing, and refurbishing process, click here.

If you cannot find the refurbished firewalls you are looking for, please call one of our account executives at 1-800-998-9862 for a custom quote. If you are not sure which firewall you need, we have technicians on staff experienced with networking products that can help you with your configurations.

We both buy and sell new, used and refurbished firewalls and other networking accessories. Let us know if you have any surplus of firewalls that you are looking to sell and we will immediately reply with fair market value. Please call our purchasing department at 1-800-998-9862 ext 354. Below is a listing of some of our more popular firewalls. If you are looking to buy firewalls at a great price, then Network Liquidators is for you.
Cisco Firewalls
Cisco PIX Firewalls
Cisco Firewall Base Units
Firewall Interface Cards
Firewall Parts & Components
Firewall Memory
Firewall Cables
All Cisco PIX Firewall Equipment

Cisco Firewall Memory

Cisco PIX-515-MEM-32 Firewall Memory


Cisco PIX-515-MEM-128 Firewall Memory

What are Firewalls?

A firewall is a system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

Firewall Techniques:

Packet filter:
Looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.

Application gateway:
Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation.

Circuit-level gateway:
Applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking.

Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.
Cisco Firewalls
firewalls
Cisco PIX-515 Firewall
Cisco PIX-515-R-BUN Firewall
Cisco PIX-515E Firewall


Cisco PIX-520 Firewall
Cisco PIX-520-FO-BUN Firewall

Cisco Firewall Interface Cards


Cisco PIX-4FE-66 Interface Card


Cisco PIX-1GE-66 Interface Card