Everyone knows a firewall between the intranet and Internet is a good idea, but did you know that barriers inside the network also serve an important function? This tip, excerpted from Dr. Jurgen Schneider's "SAP System Security for the Intranet and Internet" in the April, May, June 2001 issue of SAP Insider, covers ways that you can secure a network to protect data from internal as well as external attacks.
A well-designed network features different protection zones and only a very few well-known and protected transitions between these zones. To get from one zone to another, communication traffic has to pass through a firewall system. Nowadays, everybody expects a firewall between a company's intranet and the public Internet. Fewer people recognize the value of firewalls inside the corporate network, separating mission-critical SAP applications and database servers from the hundreds and thousands of PCs and user workstations in the client network.
How sure are you about the intentions of your internal users, and the nature and modification status of the software installed on their PCs? Just as you set up "Demilitarized Zones" (DMZs) at the border between the Internet and your intranet, and place Web servers and proxies between an external and an internal firewall, inside your corporate network you need well-configured network routers, address and port filters, and so on. A secure network can also be complemented nicely by VPNs (Virtual Private Networks) extending your extranet to customers and partners.
With such a network setup, there are only a few doors left vulnerable to penetration by intruders. Your firewalls do have these doors (otherwise you couldn't go in yourself), so you must put guards in place. These guards include strong authentication and access control, as well as encrypted communications.
All commercial Web servers, and the SAP product components they host today, support the Internet standard protocol Secure Sockets Layer (SSL) and can run HTTP over SSL, (called HTTPS). With Https, you ensure that clients and servers can be authenticated to one another via strong cryptography, and that they exchange strong encryption key information to protect all their communications from eavesdropping and message tampering. For the classical SAP communication protocols (DIAG, RFC), the same level of protection is achieved using SAP's Secure Network Communications (SNC) option and the SAProuter software as an application-level gateway.
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