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Cisco ASDM User Guide
OL-16647-01
Chapter 18 Firewall Mode Overview
Transparent Mode Overview
7. The security appliance performs NAT by translating the mapped address to the real address,
10.1.2.27.
An Outside User Visits a Web Server on the Inside Network
Figure 18-10 shows an outside user accessing the inside web server.
Figure 18-10 Outside to Inside
The following steps describe how data moves through the security appliance (see Figure 18-10):
1. A user on the outside network requests a web page from the inside web server.
2. The security appliance receives the packet and adds the source MAC address to the MAC address
table, if required. Because it is a new session, it verifies that the packet is allowed according to the
terms of the security policy (access lists, filters, AAA).
For multiple context mode, the security appliance first classifies the packet according to a unique
interface.
3. The security appliance records that a session is established.
4. If the destination MAC address is in its table, the security appliance forwards the packet out of the
inside interface. The destination MAC address is that of the downstream router, 209.186.201.1.
Host
209.165.201.2
209.165.201.1
209.165.200.230
Web Server
209.165.200.225
Management IP
209.165.201.6
Internet
92409