Cisco FirePOWER ASA 5500 series User Manual

17-15
Cisco Security Appliance Command Line Configuration Guide
OL-10088-01
Chapter 17 Applying NAT
Configuring NAT Control
Figure 17-12 shows a web server and DNS server on the outside. The security appliance has a static
translation for the 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 address, 209.165.20.10. Because you want
inside users to use the mapped address for ftp.cisco.com (10.1.2.56) you need to configure DNS reply
modification for the static translation.
Figure 17-12 DNS Reply Modification Using Outside NAT
See the following command for this example:
hostname(config)# static (outside,inside) 10.1.2.56 209.165.201.10 netmask 255.255.255.255
dns
Configuring NAT Control
NAT control requires that packets traversing from an inside interface to an outside interface match a NAT
rule. See the “NAT Control” section on page 17-3 for more information.
To enable NAT control, enter the following command:
hostname(config)# nat-control
To disable NAT control, enter the no form of the command.
ftp.cisco.com
209.165.201.10
DNS Server
Outside
Inside
User
10.1.2.27
Static Translation on Inside to:
10.1.2.56
130022
1
2
7
6
5
4
3
DNS Query
ftp.cisco.com?
DNS Reply
209.165.201.10
DNS Reply Modification
209.165.201.10 10.1.2.56
DNS Reply
10.1.2.56
FTP Request
209.165.201.10
Dest Addr. Translation
209.165.201.1010.1.2.56
FTP Request
10.1.2.56
Security
Appliance

Cisco FirePOWER ASA 5500 series Specifications

General

Brand	Cisco
Model	FirePOWER ASA 5500 series
Category	Firewall
Language	English