今天在一台linux主機下在使用mail命令發送郵件時，報如下錯誤：
send-mail: warning: inet_protocols: disabling IPv6 name/address support: Address family not supported by protocol
postdrop: warning: inet_protocols: disabling IPv6 name/address support: Address family not supported by protocol
根據報錯信息，應該是與postfix服務器的配置文件中的inet_protocols有關系，於是找到其主配置文件 /etc/postfix/main.cf
發現inet_protocols的值被配置成了all (想起應該是系統升級后，將postfix也升級了，也覆蓋了之前的配置)，
# Enable IPv4, and IPv6 if supported inet_protocols = all
解決方法（根據自己的服務器所在環境而修改,如下relayhost為新增行）：
[qq_5201351@localhost ~]$ grep -E "^inet_protocols|^relayhost" /etc/postfix/main.cf inet_protocols = ipv4 relayhost = 10.10.1.130:25
注：不能寫成IPv4，最后讓postfix重加載一下配置，發送郵件，測試，問題解決~、
最后，附其他有效配置，記錄一下，內容如下：
[qq_5201351@localhost ~]$ cat /etc/postfix/main.cf |grep ^# -v |grep ^$ -v queue_directory = /var/spool/postfix command_directory = /usr/sbin daemon_directory = /usr/libexec/postfix data_directory = /var/lib/postfix mail_owner = postfix inet_interfaces = localhost inet_protocols = ipv4 mydestination = $myhostname, localhost.$mydomain, localhost unknown_local_recipient_reject_code = 550 relayhost = 10.10.1.130:25 alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases debug_peer_level = 2 debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5 sendmail_path = /usr/sbin/sendmail.postfix newaliases_path = /usr/bin/newaliases.postfix mailq_path = /usr/bin/mailq.postfix setgid_group = postdrop html_directory = no manpage_directory = /usr/share/man sample_directory = /usr/share/doc/postfix-2.10.1/samples readme_directory = /usr/share/doc/postfix-2.10.1/README_FILES
尊重別人的勞動成果 轉載請務必注明出處：https://www.cnblogs.com/5201351/p/15500154.html