Creating user defined namespaces - BlueCat Edge - Service Point v4.x.x

Create a user defined namespace to define how to resolve DNS queries from specified domains.

1. In the top navigation bar, click and select Namespaces.
2. To add a new namespace, click New and select User defined.
3. Enter the name and description.
4. Select Cisco Umbrella integration to configure the namespace to use the Cisco Umbrella integration. If you select this option, you can also select Encrypt queries using DNS over HTTPS which ensures queries that are routed to Cisco Umbrella are encrypted.
   Attention:

   • Selecting Cisco Umbrella integration displays a message indicating that the two applicable Cisco Umbrella IP addresses have been added to the Forwarders field.
   • Selecting Encrypt queries using DNS over HTTPS disables the Forwarder field and adds the URL that is used for encrypting the queries that are routed to Cisco Umbrella.
5. Select Set TTL for DNS records to override the TTL of the DNS response. In the Maximum TTL field, enter the TTL of the response in seconds. The value must be between 0 and 2147483647 inclusively.
6. Select Set TTL for negative responses to serve DNS responses that return NXDOMAIN based on the defined TTL. In the Negative Cache TTL field, enter the maximum TTL applied to responses that return NXDOMAIN responses, in seconds. The value must be between 0 and 2147483647 inclusively.
7. Select EDNS Client Subnet to configure the EDNS Client Subnet (ECS) option. The ECS option allows the namespace to forward the subnet information in DNS queries to downstream servers for geographical evaluation. In the IPv4 Source Prefix field, enter a number between 0-32 of the IPv4 prefix of the subnet. In the IPv6 Source Prefix field, enter a number between 0-128 of the IPv6 prefix of the subnet.

   If you select Override, the namespace applies the specified IPv4 or IPv6 prefix as the ECS value, overriding any existing ECS value of incoming DNS queries. On the response, the inbound ECS value will be restored.

   If Override is not selected, the existing ECS value is forwarded in queries and responses if the value is present on the incoming query. For queries that do not contain an ECS value, one will be added using the specified IPv4 Source Prefix or IPv6 Source Prefix. On the response, the inbound ECS value will be restored.

   If you do not configure the EDNS Client Subnet fields, the ECS value is removed from incoming DNS queries before they are forwarded, but is restored on the response.

8. The Serve Expired Queries from cache option allows you to get answers from cache expired responses when responses would be SERVFAIL, or answers cannot be retrieved and generate SERVFAIL for various reasons, such as timeout. Select one of the following options:
   • Do not serve expired queries from cache
   • Serve expired queries from cache for a period of 1 hour from time of expiry (Default)
   • Serve expired queries from cache for a period of 24 hours from time of expiry
9. For Forwarders, type one or more remote DNS server IPv4 or IPv6 addresses. Optionally, you can define a custom port number or forwarders that listen on ports other than the standard DNS port. For example, 1.2.3.4:123 for IPv4 addresses or [2001:db8:1111:2222:3333:4444:5555:6666:7777]:123 for IPv6 addresses.

   If you are configuring a Discovered namespace, under Fallback forwarders, type one or more fallback remote DNS server IPv4 or IPv6 addresses.

   Attention:

   • If you do not define a port, the BlueCat Edge Service Point forwards all queries on destination port 53.
   • If you modify the forwarders of an existing namespace, the cached answer to a query might differ from what the newly configured forwarder would return. BlueCat recommends clearing the cache of the site once a forwarder has been modified to ensure that the DNS resolver service uses the answer from the updated forwarder. For more information on clearing the cache of a site, refer to Clearing the cache of DNS resolver service.
   As you enter addresses, they appear below the Forwarders field. You can enter multiple addresses separated by commas. To remove an address, click the blue X beside it.

   Note:

   • You must only use IPv4 or IPv6 destinations supported by the service point network connection. For example, if you configure the service point using only an IPv4 address, the forwarders must only be IPv4 addresses.
   • If you configure multiple forwarders within a namespace, queries are load balanced based on the following criteria:
     • The server with the least number of queries 'in the air' is selected.
     • In the event of a tie, the server with the lowest measured latency is selected. The lowest measured latency is calculated over an average on the last 128 queries answered by that server.
   • BlueCat Edge performs a health check on all configured forwarders in a namespace. If a server is unreachable, it is skipped and the next forwarder is used.
10. For Response Codes, enter one or more DNS query response codes. The DNS query response code can be one of the following:
    • NOERROR
    • NODATA
    • FORMERR
    • SERVFAIL
    • NXDOMAIN
    • NOTIMP
    • REFUSED
    • YXDOMAIN
    • YXRRSET
    • NXRRSET
    • NOTAUTH
    • NOTZONE
    • DSOTYPENI
    • BADVERS
    • BADSIG
    • BADKEY
    • BADTIME
    • BADMODE
    • BADNAME
    • BADALG
    • BADTRUNC
    • BADCOOKIE

    If any of the configured DNS query responses are returned to this namespace, the next namespace within a site will attempt to resolve the DNS queries. By default, NXDOMAIN is configured.

    Note: NODATA is a specific case of the NOERROR DNS response code that occurs when a query receives a response with no record matching the query type. If you configure the NODATA response code, Edge uses the next namespace within a site to attempt DNS query resolution.
    Note: This only applies to sites configured with more than one namespace.
11. Add domain lists (optional):
    • Under Match List, enter the domain list(s) you want this forwarder to be used for. If there is no match list, then this namespace will be used for all queries, except any exceptions.

      If you are configuring a Discovered namespace, under Additional match list, enter the additional IP list(s) that you want this forwarder to be used for. If there is no match list, then this namespace will be used for all queries matching the Discovered match list.

    • Under Exception List, add any domain list(s) that contain exceptions, if applicable.
    In total, you can add up to 20 domain lists, each with a maximum of 100,000 domains. Also, there is a 100 MB limit to the combined size of all domain lists associated with all of the namespaces.

    • If match lists are added, the namespace applies to queries matching the domains in the list.
    • If a query is in both the match list and the exception list, the exception applies.
    • If no match lists are added, the namespace applies to all queries other than those in exception lists.
12. Add IP lists (optional):
    • Under Match List, enter the IP list(s) you want this forwarder to be used for. If there is no match list, then this namespace will be used for all queries, except any exceptions.
    • Under Exception List, add any IP list(s) that contain exceptions, if applicable.
13. Click Save.
14. To delete a namespace, select it and click Delete. If the namespace is active and associated with one or more sites, you can't delete the namespace unless you deactivate it.