During SmartConnect configuration, consider the following points:
- Disable client DNS caching, when possible. To handle client requests properly, SmartConnect requires that clients use the latest DNS entries. If clients cache SmartConnect DNS information, they could connect to incorrect SmartConnect zone names. In this event, SmartConnect might not appear to be functioning correctly.
- If traffic is traversing firewalls, ensure that the appropriate ports are open. For example, if UDP port 53 is opened, also ensure TCP port 53 is opened.
- Certain clients perform DNS caching and might not connect to the node with the lowest load if they make multiple connections within the lifetime of the cached address. For example, this issue occurs on macOS X for certain client configurations.
- The site DNS servers must be able to communicate with the node that is currently hosting the SmartConnect service.
- Site DNS servers might not exist in the regular local subnets, or in any of the subnets that clients occupy. To enable the SmartConnect lookup process, ensure that the DNS servers use a consistent route to the cluster and back. If the site DNS server sends a lookup request that arrives through one local subnet on the cluster, but the configured cluster routing causes the response to be sent through a different subnet, it is likely that the packet will be dropped, and the lookup will fail. The solutions and considerations for SmartConnect are similar to the client scenarios. Also, the DNS server might benefit from a static route to the subnet that contains the SSIP address or addresses.
- SmartConnect makes it possible for different nodes to have different default routes, but this is fundamentally determined by connectivity. SmartConnect enables administrators to define multiple gateways, with one gateway per subnet. Each gateway is assigned a priority when it is defined. On any node, SmartConnect attempts to use the highest priority gateway—the gateway that has the lowest number—that has an available functioning interface in a subnet that contains the gateway address.
- OneFS release 9.2 enhances the isi network interfaces list command, providing an option to specify the type as SSIP, using the isi network interfaces list --type SSIP command.
OneFS release 9.2 introduces support for Duplicate Address Detection (DAD). For more information, see Duplicate Address Detection.