sshd安全性能优化

• sshd服务是远程登录服务，默认端口为22，对于其优化一是为了增加服务器的安全，避免暴力破解；二是为了加快速度连接，减少不必要的带宽的浪费。
• sshd服务的配置文件为/etc/ssh/sshd_config，内容默认如下：

1. # $OpenBSD: sshd_config,v 1.80 2008/07/02 02:24:18 djm Exp $
2. # This is the sshd server system-wide configuration file.  See
3. # sshd_config(5) for more information.
4. # This sshd was compiled with PATH=/usr/local/bin:/bin:/usr/bin
5. # The strategy used for options in the default sshd_config shipped with
6. # OpenSSH is to specify options with their default value where
7. # possible, but leave them commented.  Uncommented options change a
8. # default value.
9. #Port 22    修改一下默认端口，增强安全性。比如6688等。
10. #AddressFamily any
11. #ListenAddress 0.0.0.0    修改一下监听端口，默认是监听所有的IP,这样安全性不是很高，我们可以让它监听内网的Ip,这样即使有人知道系统用户的密码也无法连接进来。
12. #ListenAddress ::
13. # Disable legacy (protocol version 1) support in the server for new
14. # installations. In future the default will change to require explicit
15. # activation of protocol 1
16. Protocol 2
17. # HostKey for protocol version 1
18. #HostKey /etc/ssh/ssh_host_key
19. # HostKeys for protocol version 2
20. #HostKey /etc/ssh/ssh_host_rsa_key
21. #HostKey /etc/ssh/ssh_host_dsa_key
22. # Lifetime and size of ephemeral version 1 server key
23. #KeyRegenerationInterval 1h
24. #ServerKeyBits 1024
25. # Logging
26. # obsoletes QuietMode and FascistLogging
27. #SyslogFacility AUTH
28. SyslogFacility AUTHPRIV
29. #LogLevel INFO
30. # Authentication:
31. #LoginGraceTime 2m
32. #PermitRootLogin yes    将其改为no，不让root用户远程登录。
33. #StrictModes yes
34. #MaxAuthTries 6
35. #MaxSessions 10
36. #RSAAuthentication yes
37. #PubkeyAuthentication yes
38. #AuthorizedKeysFile     .ssh/authorized_keys
39. #AuthorizedKeysCommand none
40. #AuthorizedKeysCommandRunAs nobody
41. # For this to work you will also need host keys in /etc/ssh/ssh_known_hosts
42. #RhostsRSAAuthentication no
43. # similar for protocol version 2
44. #HostbasedAuthentication no
45. # Change to yes if you don't trust ~/.ssh/known_hosts for
46. # RhostsRSAAuthentication and HostbasedAuthentication
47. #IgnoreUserKnownHosts no
48. # Don't read the user's ~/.rhosts and ~/.shosts files
49. #IgnoreRhosts yes
50. # To disable tunneled clear text passwords, change to no here!
51. #PasswordAuthentication yes
52. #PermitEmptyPasswords no
53. PasswordAuthentication yes
54. # Change to no to disable s/key passwords
55. #ChallengeResponseAuthentication yes
56. ChallengeResponseAuthentication no
57. # Kerberos options
58. #KerberosAuthentication no
59. #KerberosOrLocalPasswd yes
60. #KerberosTicketCleanup yes
61. #KerberosGetAFSToken no
62. #KerberosUseKuserok yes
63. # GSSAPI options
64. #GSSAPIAuthentication no
65. GSSAPIAuthentication yes   将这个值改为no ，加快连接速度。
66. #GSSAPICleanupCredentials yes
67. GSSAPICleanupCredentials yes
68. #GSSAPIStrictAcceptorCheck yes
69. #GSSAPIKeyExchange no
70. # Set this to 'yes' to enable PAM authentication, account processing,
71. # and session processing. If this is enabled, PAM authentication will
72. # be allowed through the ChallengeResponseAuthentication and
73. # PasswordAuthentication.  Depending on your PAM configuration,
74. # PAM authentication via ChallengeResponseAuthentication may bypass
75. # the setting of "PermitRootLogin without-password".
76. # If you just want the PAM account and session checks to run without
77. # PAM authentication, then enable this but set PasswordAuthentication
78. # and ChallengeResponseAuthentication to 'no'.
79. #UsePAM no
80. UsePAM yes
81. # Accept locale-related environment variables
82. AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
83. AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
84. AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE
85. AcceptEnv XMODIFIERS
86. #AllowAgentForwarding yes
87. #AllowTcpForwarding yes
88. #GatewayPorts no
89. #X11Forwarding no
90. X11Forwarding yes
91. #X11DisplayOffset 10
92. #X11UseLocalhost yes
93. #PrintMotd yes
94. #PrintLastLog yes
95. #TCPKeepAlive yes
96. #UseLogin no
97. #UsePrivilegeSeparation yes
98. #PermitUserEnvironment no
99. #Compression delayed
100. #ClientAliveInterval 0
101. #ClientAliveCountMax 3
102. #ShowPatchLevel no
103. #UseDNS yes                 将yes改为no，不适用dns，我们本来就是用ip访问的。
104. #PidFile /var/run/sshd.pid
105. #MaxStartups 10:30:100
106. #PermitTunnel no
107. #ChrootDirectory none
108. # no default banner path
109. #Banner none
110. # override default of no subsystems
111. Subsystem       sftp    /usr/libexec/openssh/sftp-server
112. # Example of overriding settings on a per-user basis
113. #Match User anoncvs
114. #       X11Forwarding no
115. #       AllowTcpForwarding no
116. #       ForceCommand cvs server

 

总结：修改5个地方

1，默认端口           Port 52113

2，不使用dns解析  UseDNS no

3，不让root用户直接登录  PermitRootlogin no 

4，GSSAPI验证改为no GSSAPIAuthentication no

5, 监听端口ip 改为内网的Ip。