winframework / winphp

        foreach ($hosts as $hostentry) {

            $hostinfo = [];

            if (!preg_match(

                '/^((ssl|tls):\/\/)*([a-zA-Z0-9\.-]*|\[[a-fA-F0-9:]+\]):?([0-9]*)$/',

                trim($hostentry),

                $hostinfo

            )) {

                static::edebug($this->lang('connect_host') . ' ' . $hostentry);

                // Not a valid host entry

                continue;

            }

            // $hostinfo[2]: optional ssl or tls prefix

            // $hostinfo[3]: the hostname

            // $hostinfo[4]: optional port number

            // If it's not specified, the default value is used

            //Check the host name is a valid name or IP address before trying to use it

            if (!static::isValidHost($hostinfo[3])) {

                static::edebug($this->lang('connect_host') . ' ' . $hostentry);

                continue;

            }

            $prefix = '';

            $secure = $this->SMTPSecure;

            $tls = ('tls' == $this->SMTPSecure);