Cisco Catalyst 6500 Series Configuration Manual page 159

Chapter 9 Configuring Network Address Translation
Figure 9-6
outside server. In this case, when an inside user requests the address for ftp.cisco.com from the DNS
server, the DNS server responds with the real local address, 209.165.20.10. Because you want inside
users to use the translated global address for ftp.cisco.com (10.1.2.56) you need to configure DNS reply
modification for the static translation.
Figure 9-7
3
DNS Reply Modification
209.165.201.10
See the following command for this example:
FWSM/contexta(config)# static (outside,inside) 10.1.2.56 209.165.201.10 netmask
255.255.255.255 dns
OL-6392-01
shows a web server and DNS server on the outside. The FWSM has a static translation for the
DNS Reply Modification Using Outside NAT
1
DNS Query
ftp.cisco.com?
2
DNS Reply
209.165.201.10
10.1.2.56
4
DNS Reply
10.1.2.56
Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Configuration Guide
ftp.cisco.com
209.165.201.10
Static Translation on Inside to:
10.1.2.56
DNS Server
Outside
10.1.2.56
FWSM
FTP Request
Inside
User
10.1.2.27
NAT Overview
7
FTP Request
209.165.201.10
6
Dest Addr. Translation
209.165.201.10
5
10.1.2.56
9-15