Tunnel mode is used in the security gateway at one end or both ends of the structure, such as a router or firewall with IPSec. Using the tunnel mode, many hosts do not need to install firewall can secure IPSec communications. Generated by these hosts unprotected network packets through the external network, the use of tunnel mode security organization provides transmission. The following is the IPSec tunnel mode operation example. A host of a network generates an IP packet, the destination address is another network host B. This packet is sent from the originating host to host a secure network edge router or firewall. Firewall packet filtering all out to see which packages need for IPSec processing. If the packet from A to B need to use IPSec, firewall for IPSec processing, and the net bag pack, add the outer IP header. The outer header source address is a firewall, and host B destination address may be the edge of the network firewall. Now the package delivered to the host Bs firewall, the router checks only way the outer IP header. B will host the networks firewall to get rid of the outer IP header, the IP sent to the host B to the inner layer.
The two companies work together over the past decade has been developing products for mobile device security software and network equipment development. For example, Nokias network equipment technology allows the formation of cluster groups each VPN and firewall device for use with the aim of improving performance and stability. The deal is expected to be completed in the first quarter, trading conditions are not public. Traditionally, Microsoft is usually listed in the new version of the operating system after 6 months, to no longer allow the old version of the operating system shipped in the market. But the launch of Windows Vista nearly two years, Windows XP also continued on the market. Since January 2007 since the advent of Vista, Microsoft is the third extension of the validity of the XP. The end of January next year, PC makers are still buying XP license deadlines, but before May 30 next year, PC makers can still accept the XP license. Therefore, the user before the end of June next year, you can buy pre-installed Windows XP machine.