Linux默认端口占用问题
1.显示当前临时端口的范围：
一般情形下：linux临时端口号范围是(32768，61000)
sysctl net.ipv4.ip_local_port_range或cat /proc/sys/net/ipv4/ip_local_port_range
2.暂时性修改临时端口的范围：
echo 1024 65535 > /proc/sys/net/ipv4/ip_local_port_range
注意以上命令是在root用户时执行的！！
或者 sudo sysctl -w net.ipv4.ip_local_port_range="1024 64000"
3.永久性修改：
修改文件 /etc/sysctl.conf
键入如下语句：net.ipv4.ip_local_port_range = 1024 65535
4.受限端口列表：
| 端口 | 原因 |
|---|---|
| 1 | tcpmux |
| 7 | echo |
| 9 | discard |
| 11 | systat |
| 13 | daytime |
| 15 | netstat |
| 17 | qotd |
| 19 | chargen |
| 20 | ftp data |
| 21 | ftp access |
| 22 | ssh |
| 23 | telnet |
| 25 | smtp |
| 37 | time |
| 42 | name |
| 43 | nicname |
| 53 | domain |
| 77 | priv-rjs |
| 79 | finger |
| 87 | ttylink |
| 95 | supdup |
| 101 | hostriame |
| 102 | iso-tsap |
| 103 | gppitnp |
| 104 | acr-nema |
| 109 | pop2 |
| 110 | pop3 |
| 111 | sunrpc |
| 113 | auth |
| 115 | sftp |
| 117 | uucp-path |
| 119 | nntp |
| 123 | NTP |
| 135 | loc-srv /epmap |
| 139 | netbios |
| 143 | imap2 |
| 179 | BGP |
| 389 | ldap |
| 465 | smtp+ssl |
| 512 | print / exec |
| 513 | login |
| 514 | shell |
| 515 | printer |
| 526 | tempo |
| 530 | courier |
| 531 | chat |
| 532 | netnews |
| 540 | uucp |
| 556 | remotefs |
| 563 | nntp+ssl |
| 587 | stmp? |
| 601 | ?? |
| 636 | ldap+ssl |
| 993 | ldap+ssl |
| 995 | pop3+ssl |
| 2049 | nfs |
| 3659 | apple-sasl / PasswordServer |
| 4045 | lockd |
| 6000 | X11 |
| 6665 | Alternate IRC [Apple addition] |
| 6666 | Alternate IRC [Apple addition] |
| 6667 | Standard IRC [Apple addition] |
| 6668 | Alternate IRC [Apple addition] |
| 6669 | Alternate IRC [Apple addition] |
