IPv6 support

EGO supports IPv6. Among other benefits of IPv6, longer address lengths (128 bit) result in increased address availability for networked devices, which allows you to allocate addresses in large blocks.

EGO and IPv6

The following notes provide information on EGO support for IPv6:
  • Scope: You must assign global unicast addresses to IPv6-enabled hosts.
  • Compatibility: IPv4 and IPv6 hosts can communicate only with corresponding hosts of the same type or with dual-stack hosts. However, dual-stack hosts can communicate with both IPv4 and IPv6 hosts, allowing compatibility between the two host types. Therefore, if you have a mixed cluster with both IPv4 and IPv6 hosts, configure it to be dual-stack.
  • DNS cache: To locally store host names and mapped addresses (both IPv4 and IPv6 types), EGO uses a host DNS cache.
  • Hosts file: You can define a hosts file to provide address-to-name translation. Create hosts in $EGO_CONFDIR (Linux®) or %EGO_CONFDIR% (Windows). This file is most useful if you have multi-homed hosts (hosts with multiple interface cards or nics) or dual-stack hosts. It assists you in authenticating hosts, and viewing host mappings in cases where there are multiple addresses and names.

Configuring IPv6 support

To enable, disable, or configure IPv6 support, set these parameters:
Table 1. IPv6 configuration parameters
Parameter Variables Default File name and location
EGO_DHCP_ENV
  • Undefined (client's IP addresses are cached)
  • Defined (client's IP addresses are not cached; enables dynamic IP addressing for all client hosts in cluster)

If defined, you must also define EGO_DYNAMIC_HOST_WAIT_TIME for hosts to rejoin a cluster after their IP address changes.

 Undefined
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
EGO_DUALSTACK_PREFER_IPV6
  • Y (returns IPv6 at front)
  • N (returns IPv4 at front)

Meaningful for dual-stack hosts. If set, a dual-stack host uses IPv6 instead of IPv4 to communicate with other IPv6 or dual-stack hosts. (See note.)

 N (IPv4 at front)
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
EGO_ENABLE_SUPPORT_IPV6
  • Y (to enable)
  • N (to disable)

Enabling support for IPv6 does not have any effect IPv4-only hosts. If set to N, IPv6-only hosts are not recognized.

 N (disabled)
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
EGO_HOST_CACHE_DISABLE
  • Y (to disable)
  • N (to enable)
 N (enable caching of host names and addresses)
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
EGO_HOST_CACHE_NTTL Negative time to live, in seconds

The amount of time that errors are cached.

 20 seconds

(to turn off caching completely, set to 0)
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
EGO_HOST_CACHE_PTTL Positive time to live, in seconds

The amount of time cached results are stored.

 86400 seconds (24 hours)

(to turn off caching completely, set to 0)
  • Linux: $EGO_CONFDIR/ego.conf
  • Windows: %EGO_CONFDIR%\ego.conf
Note: Set EGO_DUALSTACK_PREFER_IPV6 in the ego.conf file to sort address presentation in the cache library. For example, set EGO_DUALSTACK_PREFER_IPV6 to Y so that IPv6 addresses appear first on the list; set it to N so that IPv4 addresses appear first. This parameter affects only the sort order of the list and communication between dual-stack hosts. It does not enable IPv6, nor does it filter the address list.