C H A P T E R
1-1
Cisco ASA Series CLI Configuration Guide
1
Configuring Dynamic DNS
This chapter describes how to configure DDNS update methods and includes the following topics:
•
Information About DDNS, page 1-1
•
Licensing Requirements for DDNS, page 1-2
•
Guidelines and Limitations, page 1-2
•
•
Configuration Examples for DDNS, page 1-3
•
DDNS Monitoring Commands, page 1-6
•
Feature History for DDNS, page 1-6
Information About DDNS
DDNS update integrates DNS with DHCP. The two protocols are complementary: DHCP centralizes and
automates IP address allocation; DDNS update automatically records the association between assigned
addresses and hostnames at predefined intervals. DDNS allows frequently changing address-hostname
associations to be updated frequently. Mobile hosts, for example, can then move freely on a network
without user or administrator intervention. DDNS provides the necessary dynamic update and
synchronization of the name-to-address mapping and address-to-name mapping on the DNS server. To
configure the DNS server for other uses, see the
“Configuring the DNS Server” section on page 1-12
. To
configure DHCP, see the
“Configuring a DHCP Server” section on page 1-3
EDNS allows DNS requesters to advertise the size of their UDP packets and facilitates the transfer of
packets larger than 512 octets. When a DNS server receives a request over UDP, it identifies the size of
the UDP packet from the OPT resource record (RR) and scales its response to contain as many resource
records as are allowed in the maximum UDP packet size specified by the requester. The size of the DNS
packets can be up to 4096 bytes for BIND or 1280 bytes for the Windows 2003 DNS Server. Several
additional
message-length maximum
commands are available:
•
The existing global limit:
message-length maximum 512
•
A client or server specific limit:
message-length maximum client 4096
•
The dynamic value specified in the OPT RR field:
message-length maximum client auto
If the three commands are present at the same time, the ASA enforces the minimum of the three specified
values.
Summary of Contents for 5505 - ASA Firewall Edition Bundle
Page 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Page 61: ...P A R T 1 Getting Started with the ASA ...
Page 62: ......
Page 219: ...P A R T 2 Configuring High Availability and Scalability ...
Page 220: ......
Page 403: ...P A R T 2 Configuring Interfaces ...
Page 404: ......
Page 499: ...P A R T 2 Configuring Basic Settings ...
Page 500: ......
Page 533: ...P A R T 2 Configuring Objects and Access Lists ...
Page 534: ......
Page 601: ...P A R T 2 Configuring IP Routing ...
Page 602: ......
Page 745: ...P A R T 2 Configuring Network Address Translation ...
Page 746: ......
Page 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
Page 846: ......
Page 981: ...P A R T 2 Configuring Access Control ...
Page 982: ......
Page 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
Page 1062: ......
Page 1093: ...P A R T 2 Configuring Application Inspection ...
Page 1094: ......
Page 1191: ...P A R T 2 Configuring Unified Communications ...
Page 1192: ......
Page 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
Page 1334: ......
Page 1379: ...P A R T 2 Configuring Advanced Network Protection ...
Page 1380: ......
Page 1475: ...P A R T 2 Configuring Modules ...
Page 1476: ......
Page 1549: ...P A R T 2 Configuring VPN ...
Page 1550: ......
Page 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
Page 1966: ......
Page 2059: ...P A R T 2 System Administration ...
Page 2060: ......
Page 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Page 2099: ...P A R T 2 Reference ...
Page 2100: ......