Cisco 7604 Configuration Guide - Page 119
An Inside User Visits a Web Server, Inside to Outside
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Chapter 5 Configuring the Firewall Mode An Inside User Visits a Web Server Figure 5-9 shows an inside user accessing an outside web server. Figure 5-9 Inside to Outside www.example.com Transparent Mode Overview Internet FWSM 209.165.201.2 Management IP 209.165.201.6 92892 Host 209.165.201.3 The following steps describe how data moves through the FWSM (see Figure 5-9): 1. The user on the inside network requests a web page from www.example.com. 2. The FWSM 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 FWSM first classifies the packet according to a unique interface. 3. The FWSM records that a session is established. 4. If the destination MAC address is in its table, the FWSM forwards the packet out of the outside interface. The destination MAC address is that of the upstream router, 209.165.201.2. If the destination MAC address is not in the FWSM table, the FWSM attempts to discover the MAC address by sending an ARP request and a ping. The first packet is dropped. 5. The web server responds to the request; because the session is already established, the packet bypasses the many lookups associated with a new connection. 6. The FWSM forwards the packet to the inside user. OL-20748-01 Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide using ASDM 5-13
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