etc-network-interfaces-eth0

auto eth0

iface eth0 inet static
    address              10.100.1.17/16
    gateway              10.100.0.1
    up      ip addr add 10.100.245.17 dev eth0
    up      ip -4 route add default via 10.100.0.1 table default
    down    ip -4 route del default via 10.100.0.1 table default || true
    up      ip -4 rule add from 10.100.245.17 lookup default
    down    ip -4 rule del from 10.100.245.17 lookup default || true

# IPv6
iface eth0 inet6 static
    address              2001:2060:41:a64::0.0.1.17/64
    gateway              2001:2060:41:a64::1
    up      ip -6 addr add 2001:2060:41:a64::0.0.245.17 dev eth0
    up      ip -6 route add default via 2001:2060:41:a64::1 table default
    down    ip -6 route del default via 2001:2060:41:a64::1 table default || true
    up      ip -6 rule add from 2001:2060:41:a64::0.0.245.17 lookup default
    down    ip -6 rule del from 2001:2060:41:a64::0.0.245.17 lookup default || true

keepalived.conf

virtual_server 194.197.235.245 6667 {
    lb_algo     rr
    lb_kind     NAT
    protocol    TCP

    real_server 10.100.245.17 6667 {

    }
}
virtual_server 2001:2060:41:240::f5 6667 {
    lb_algo     rr
    lb_kind     NAT
    protocol    TCP

    real_server 2001:2060:41:a64::0.0.245.17 6667 {

    }
}