A Domain name server (DNS) converts domain name into an Internet Protocol (IP) address which is used by computers to identify each other on a network. Domain names are alphabetic and easier to remember by humans. However the Internet is based on IP addresses. Every time you type a domain name, a DNS service translates the name into the corresponding IP address. With the help of DNS you do not have to keep your own address book of IP addresses. Instead, you just connect through a domain name server, also called a DNS server which manages a massive database that maps domain names to IP addresses. DNS has become even more important for IPv6 than it was for IPv4 due to the length of IPv6 addresses and difficulty in remembering them.
The AAAA record also known as “quad-a”is used to represent a 128-bit IPv6 address. When an IPv6 aware application wants to look up the name of an IPv6 server, it will request an quad-a record from the DNS server. (Just as a reminder: in IPv4, applications request the A, for "Address," record to translate names to addresses.)
If a DNS server does not have an IP address of a particular domain name, that DNS server sends a request to another DNS server, and so on, this process continues until the correct IP address is returned.
The DNS feature on Seqrite UTM allows you to override the default Domain Name Server settings and enter the details of the DNS provided by your ISP or specify a particular DNS that you want to use. You can also change the priority of DNS. This feature allows Seqrite UTM to try to use another DNS server in case the server you are using is unavailable.
Seqrite UTM supports the following types of DNS configuration:
· DNS Server
· Static DNS
· Dynamic DNS
Using the Global DNS server settings you can add the IP address of the DNS provided by your ISP. You can add an IPv6 or IPv4 IP address. An IP address in the IPV4 standard has four numbers separated by three decimals, as in: 220.127.116.11. An IP address in the IPV6 standard has eight hexadecimal numbers (base-16) separated by colons, as shown below:
Note: You can add IPv6 DNS only if IPv6 feature is enabled on Seqrite UTM. For more details on IPV6 feature see the IPv6 section.
By default the DNS with IP address 18.104.22.168 is used.
Adding DNS server for IPv6
1. Navigate to Network > DNS > DNS Servers. The DNS page is displayed which contains the list of DNS servers.
2. Click the + (Add) icon displayed on the right hand corner of the DNS table. The add DNS Servers dialog box is displayed.
3. Enter the IPv6 address of the DNS server and click Save.
Deleting Global DNS servers
1. Navigate to Network > DNS > DNS Servers. The Global DNS page is displayed which contains the list of DNS servers..
2. Select the server you want to delete and click the Delete icon. You can select and delete multiple servers at the same time.
3. Click Apply.
Flushing DNS Cache for IPv6
The DNS uses a cache to temporarily store the IP address records. Each of these record has an expiration date (TTL: Time-To-Live) after which it will be deleted. However, you can empty the cache manually i.e. if you want recent changes in DNS records to take effect immediately without waiting for the TTL to expire.
1. Navigate to Network > DNS > DNS Servers. The DNS Servers page is displayed.
2. Click Flush DNS Cache. The cache is flushed and contents are deleted.
If you know the IPv6 address of a host, then you can add a static DNS entry for the hosts on Seqrite UTM. Whenever you access this host, Seqrite UTM will resolve and return the added IPv6 address.
Adding a Static DNS entry for IPv6
1. Navigate to Network > DNS > Static. The Static DNS page is displayed with a list of DNS servers. If no DNS servers are listed, you need to add a DNS server.
2. Click the + (Add) icon. The Add static DNS popup is displayed.
3. Enter the Host Name and IPv6 address. Note: The host name must be a FQDN (Fully qualified Domain name ). for example www.google.com is FQDN and its ipv6 address is 2001:4860:4860::8888
4. Click Save.
Deleting a Static DNS entry for IPv6.
1. Navigate to Network > DNS > DNS Static. The Static DNS page is displayed with a list of Static DNS servers.
2. Select the server you want to delete and click the Delete icon. You can also select and delete multiple Static DNS servers at a time.
For assistance please write us @ UTMSupport@Seqrite.com