filteredForSource := t.applyCombinationFilters(fromInstance, t.destinations)
		// make sure this targets the same deployments (not necessarily the same instances)
		targetNames := filteredForSource.Services().FQDNs()
		if len(commonTargets) == 0 {
			commonTargets = targetNames
		} else if !slices.Equal(targetNames, commonTargets) {

	if 1 <= port && port <= 65535 {
		return nil
	}
	return fmt.Errorf("port number %d must be in the range 1..65535", port)
}

// encapsulates DNS 1123 checks common to both wildcarded hosts and FQDNs
func CheckDNS1123Preconditions(name string) error {
	if len(name) > 255 {
		return fmt.Errorf("domain name %q too long (max 255)", name)
	}
	if len(name) == 0 {
		return fmt.Errorf("empty domain name not allowed")

	// If this service entry had endpoints with IPs (i.e. resolution STATIC), then we do EDS update.
	// If the service entry had endpoints with FQDNs (i.e. resolution DNS), then we need to do
	// full push (as fqdn endpoints go via strict_dns clusters in cds).
	if len(unchangedSvcs) > 0 {
		if isDNSTypeServiceEntry(currentServiceEntry) {

		// the real "foo.com"
		// This works by providing a list of domains that were added as expanding the DNS domain as part of expandedHosts,
		// and a list of known unexpanded FQDNs to compare against
		if slices.Contains(expandedHosts, d) && knownFQDNs.Contains(d) { // O(n) search, but n is at most 10
			continue
		}
		temp = append(temp, d)
		vhdomains.Insert(strings.ToLower(d))
	}

	}
	if c.conn != nil {
		return c.conn.RemoteAddr().String()
	}
	return ""
}

// hostnameInSNI converts name into an appropriate hostname for SNI.
// Literal IP addresses and absolute FQDNs are not permitted as SNI values.
// See RFC 6066, Section 3.
func hostnameInSNI(name string) string {
	host := name
	if len(host) > 0 && host[0] == '[' && host[len(host)-1] == ']' {
		host = host[1 : len(host)-1]

	for i := range vservices {
		vservices[i] = virtualServices[i].DeepCopy()
	}

	totalVirtualServices.Record(float64(len(virtualServices)))

	// convert all shortnames in virtual services into FQDNs
	for _, r := range vservices {
		resolveVirtualServiceShortnames(r.Spec.(*networking.VirtualService), r.Meta)
	}