Php 使用带后缀的ip地址代替域名

我正在尝试做的是（只）向任何在我的网站上注册的人发送一封verficstion电子邮件。我已经编写了php代码，非常简单

$to      = '//my email address for testing ex:user@gmail.com';
$subject = 'Signup | Verification';
$message = '
//email body
';          
$headers = '<From:noreply@[//my Ip address]' . "\r\n";
mail($to, $subject, $message, $headers);
var_dump(mail($to, $subject, $message, $headers));

这应该是服务器故障吗？我是删除它并将其发布在那里还是仅将其发布在那里

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
# fresh installs.
compatibility_level = 2



# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtp_tls_security_level = may

smtp_tls_CApath=/etc/ssl/certs
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache


smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = localdomain 
#this (localdomain) is set in /etc/hosts to my ip adress
#most of the stuff is set to defualt values such as tls things
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
myorigin = /etc/mailname
mydestination = $myhostname, pop-os.localdomain, localhost.localdomain, localhost


smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = static:USERNAME:PASSWORD
smtp_sasl_security_options = noanonymous 


relayhost = 

mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = loopback-only
inet_protocols = ipv4