Note: Cisco Systems cannot correct
your DNS problem. Only both your SysAdmin and Internet Service Provider
can. The following is offered to help you understand DNS.
What is DNS?
The Internet's Domain Name Service (DNS) provides a way to map a numerical
IP address to an alphanumeric name. For example, Cisco Connection Online
is currently at IP address 198.133.219.25, and has a DNS name of "www.cisco.com".
As with every computer on the Internet, your computer, to communicate
with others on the Internet, requires an IP address. DNS names are optional,
but highly encouraged for certain forms of authentication, and to ease
of management of large networks.
Do I need to be DNS registered to use CCO?
Cisco Connection Online has many pages which require a "reverse lookup"
using the Internet's Domain Name Service (DNS). This type of authentication
takes the IP address of your incoming packets, and resolves it to a specific
registered Internet Domain. By this, we can determine the organization
you are with and thereby grant entitlement to certain features and functions.
We also use this type of inquiry to record usage of our site.
If you have been assigned an IP address, but not given a DNS hostname
for your computer (or are not coming through a DNS-registered proxy server),
then this DNS lookup will fail to resolve. As well, this DNS resolution
will fail if there are any problems with the registration of your Domain,
or in case of DNS server problems.
What if the DNS resolution fails?
If you are not DNS registered, or the reverse DNS lookup fails under any
other conditions, all page accesses to Cisco Connection Online will be
considerably slower, and many will be denied to you altogether. Some sections
of Cisco Connection Online not only require the resolution of an IP address
to a domain name, but are only available if the page resolves to a specific
domain or class of domains. For instance, to obtain Cisco IOS 56-bit DES
cryptography software, your host needs to resolve to a domain registered
within the United States (among other entitlement criteria).
How do I check if I am DNS registered?
Each computer operating system and TCP/IP application suite may vary how
DNS registration of your computer works. As well, DNS may be administered
centrally through a dynamic host address (DHCP) or proxy server. In general,
contact your organization's Information Systems (IS) group, your Internet
Service Provider (ISP), or your TCP/IP software application vendor for
details and assistance in DNS registration.
How do I administer DNS services?
If you are within an IS or ISP organization, and are looking for solutions
to DNS-related issues, try the following links:
-
Cisco DNS/DHCP
Manager (CDDM) is an application suite for managing dynamic IP
address assignment and Domain Name Service (DNS) within your network.
-
If you are rather new to the Internet, your site may have been assigned
an IP address block, but is not yet a registered domain. Check out what
Yahoo
has on Internet
Domain Registration.
-
If you require detailed information regarding the function and specification
of DNS services, check out the
DNS
Resources Directory maintained by The
Internet Solution. It includes links to such resources as RFCs
and implementation tips.
More Help on CCO
Please read our CCO Help page for
other CCO usage issues.