Configure DNS on Cisco Router Using the Simple DNS Tutorial

Many people would certainly prefer to have dhcp on Cisco routers rather than any other type of standard configuration. There is certainly a lot of positive benefit to be derived from it. The most popularly preferred one is the ability to provide internet connectivity regardless of the geographical location or the time zone of the customer. The other advantages that come with it are also quite considerable. This discussion will look at some of the advantages of having this feature in your hardware.

The first advantage that you can get from it is the fact that it enables you to configure the DHCPD server before it is connected to the different Ethernet networks. There are two different types of DHCPDs that can be setup on the Cisco equipment; the first one being the repeater. It is a very powerful server that can carry out to almost a hundred hop computations and will thus be able to establish very fast connections. The second option is the multi-homed device that uses up to 100 IP addresses in it. The latter has the disadvantage of being vulnerable to attack from various other devices, but it is preferred because of the stronger encryption feature that it offers.

The next advantage is that the DNS server configuration is automated. The classic way of configuring this feature was to create a firewall between the VPN connection and the DNS server. That creates a very complicated setup and this is not preferred at all. The easy way to configure this is to set up an interface using the apt tool that comes with the software. You will have to use an IP address and a name for the interface. The length of the name should be long enough to reflect the number of IP addresses that will be used.

The next step in configuring the DHCPD is to create the private, extended IP address and associate it with the static IP of the local network. It is necessary to configure the private, extended IP as described in the section on server configuration. The duration of the private extended IP address can be anything, but it is advisable to set it as short as possible.

You can test the server configuration by trying to send a TCP or ICMP message to the IP address. If you are using ICMP, the ICMP reply will contain the IP destination as well as the reply header. If the destination does not respond, you will not know what kind of ICMP was sent. The packet tracer will help you know what kind of message was sent. You should be able to connect to your favorite IP host by typing the IP address of your favorite IP host in the packet tracer and look for the response. If you are unable to connect, then you might have to change your IP or the DNS name or the connection may have been configured incorrectly.

The main reason why you want to set up DHCPD on Cisco routers is to avoid the probability of firewall attacks. When you dislike a certain IP address, the probability that someone will attack your system is high. The attack can come from anywhere since the source IP of the packet tracer is not private and there is no guarantee that the response will be ICMP or from a trusted IP. There is also no guarantee that the ISP you are using will support DHCPD. If they do not offer DHCPD on their connection, it is not strange that you cannot connect to your favorite IP host.

There is also a probability that the firewall at your ISP will block DHCPD. This will make it impossible for you to configure DHCPD on your Cisco router. It is therefore advisable to avoid ISPs that do not offer DHCPD. Instead, you can set up DHCPD on the private internal IP network. Since the rate of intrusion into an internal private IP network is very low compared to the ISPs, it will be better for you to use DHCPD even if the connection to your favorite IP host is slow.

The next step is to find out how long it will take for the DNS client to locate your IP address in the cache of the DNS server and to establish a record for it. With this information you can calculate how long it will take for your IP address to appear in the cache and in turn determine the length of time you should set the preference for in the DNS server. In addition to that, the calculation also includes the calculation of the minimum and maximum durations of DNS queries that will help you determine the likelihood of a particular DNS client requesting an older (low priority) or newer (high priority) record. The best possible option for you is to configure a server with high priority than low priority as this will avoid DNS clients that prefer to go with the older or higher prefrences.