默认情况下，如果用作IMAP / POP代理，CentOS 7下的nginx将无法启动。 这是因为SELinux。
如何改变SELinux的configuration，而不禁用它的保护，让nginx按照需要行事？
audit.log
type=AVC msg=audit(1429125129.833:2286): avc: denied { name_bind } for pid=26451 comm="nginx" src=143 scontext=system_u:system_r:httpd_t:s0 tcontext=system_u:object_r:pop_port_t:s0 tclass=tcp_socket nginx.conf
mail { auth_http unix:/run/nginx-mailauth.sock; ssl_prefer_server_ciphers on; ssl_session_cache shared:mail-TLSSL:16m; ssl_session_timeout 10m; ssl_session_tickets on; ssl_certificate /etc/pki/tls/certs/mail.example.com.cer; ssl_certificate_key /etc/pki/tls/private/mail.example.com.key; ssl_session_ticket_key /etc/pki/tls/private/mail.example.com-session_ticket.key; ssl_protocols TLSv1 TLSv1.1 TLSv1.2; #For antimony-webmail imap_capabilities "IMAP4rev1" "ACL" "BINARY" "CATENATE" "CHILDREN" "CONDSTORE" "ENABLE" "ESEARCH" "ID" "IDLE" "LIST-EXTENDED" "LITERAL+" "MULTIAPPEND" "NAMESPACE" server { protocol imap; listen 143; starttls only; } server { protocol imap; listen 993; ssl on; } #For antimony-webmail pop3_capabilities "EXPIRE 31 USER" "TOP" "UIDL" "USER" "XOIP"; server { protocol pop3; listen 110; starttls only; pop3_auth plain; } server { protocol pop3; listen 995; ssl on; pop3_auth plain; } }
systemctl
[root@mail ~]# systemctl start nginx Job for nginx.service failed. See 'systemctl status nginx.service' and 'journalctl -xn' for details. [root@mail ~]# systemctl status nginx.service nginx.service - The nginx HTTP and reverse proxy server Loaded: loaded (/usr/lib/systemd/system/nginx.service; disabled) Active: failed (Result: exit-code) since Wed 2015-04-15 12:12:09 PDT; 5s ago Process: 26446 ExecStop=/bin/kill -s QUIT $MAINPID (code=exited, status=0/SUCCESS) Process: 25373 ExecReload=/bin/kill -s HUP $MAINPID (code=exited, status=0/SUCCESS) Process: 26400 ExecStart=/usr/sbin/nginx (code=exited, status=0/SUCCESS) Process: 26451 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=1/FAILURE) Main PID: 26402 (code=exited, status=0/SUCCESS) Apr 15 12:12:09 mail.dev.example.com nginx[26451]: nginx: the configuration file /etc/nginx/nginx.conf syntax is ok Apr 15 12:12:09 mail.dev.example.com nginx[26451]: nginx: [emerg] bind() to 0.0.0.0:143 failed (13: Permission denied) Apr 15 12:12:09 mail.dev.example.com nginx[26451]: nginx: configuration file /etc/nginx/nginx.conf test failed Apr 15 12:12:09 mail.dev.example.com systemd[1]: nginx.service: control process exited, code=exited status=1 Apr 15 12:12:09 mail.dev.example.com systemd[1]: Failed to start The nginx HTTP and reverse proxy server. Apr 15 12:12:09 mail.dev.example.com systemd[1]: Unit nginx.service entered failed state.
Nginx正在停止绑定到SELinux pop_port_t端口。
有可能将所需的端口更改为nginx可以绑定的types，例如http_port_t 。
# for port in {143,993,110,995} ; do semanage port -m -t http_port_t -p tcp $port ; done && semanage port -l -C SELinux Port Type Proto Port Number http_port_t tcp 143, 993, 110, 995