In this zone reside those services that should be in CDC's the most external part (DNS Cache, SMTP Relay and streaming Proxy/Cache).

This is a two independent VLAN zone, protected by two redundant firewalls in fileover (CISCO PIX 520), and faced by to equalizers (ALTEON ACEdirector 3).

DNS Caché

Its function is to resolve domain names with its correspondent IP addresses. Each time that a resolution petition takes place at the Primary DNS (or secondary, located in another geographical point) this one resolves and sends it to the requester client. DNS Cache memorizes recent consultations, so if another petition comes up, it will be able process it faster.

Technology:
Hardware: VA Linux 2240, two redundant and balanced systems.
Software: S.O.: Debian Linux 2.4.1 and DNS Server: BIND v. 8

SMTP Relay

SMTP's function is to redirect all mail that arrives at the CDC t the right destination

Technology:
Hardware: VA Linux 2240, two redundant and balanced systems
Software: S.O.: Debian Linux 2.4.1 and DNS server: BIND v. 8

Caché/Proxy de streaming

Located in the services' zone' public zone, in an independent sub-Web independent (to guarantee scalability), this equipment bears QT, MMT and RN, protocols, responsible for serving the client with the streaming contents. If the content is not locally chached in the proxy, next step will be to communicate via http with the corresponding streaming server. As soon as it receives the first data block, it begins to serve it. If the content is ready (cached) it will be rapidly dispatch. The proxys facilitate the administration, as dedicated appliances, improve performance and security (the proxy does not run any known operative system, and leaves contents and server isolated behind the firewalls, given that is the only framed).

Technology:
Hardware: NetApp C720S NetCache