Apranik

Fallback ​

An outbound group that uses the first member, in list order, whose probe passed.

A fallback group: every interval it probes each member. Members are listed in order of preference; server-a failed its probe, so connections use server-b, the first member that passed. server-a is used again as soon as its probe passes; members that failed are still tried, last.

Structure ​

json
{
  "tag": "failover",
  "protocol": {
    "type": "fallback",
    "settings": {
      "members": ["server-a", "server-b", "direct"],
      "probe": {
        "url": "https://www.gstatic.com/generate_204",
        "interval": "1m"
      }
    }
  }
}

A group has only tag and protocol: no server, transport or dns_server.

Fields ​

members ​

list of tagsRequired

The outbounds to use, by tag, most preferred first. A member may be another group.

probe ​

object

How members are tested. See Probe.

How it chooses ​

  • A connection tries members in list order, skipping those whose last probe failed, and uses the first that connects. Members that failed are tried last, not never.
  • When every probe fails, it uses plain list order.
  • A UDP session keeps the member it got first.
  • The group carries only the networks every member carries: one TCP-only member makes the group TCP-only.