apt出现no public key available for the following key

本来在Debian系统下想安装一些监控软件，但是，使用apt-get安装时出现了一下问题，后来google了一下，查到了这篇文章，具体出处忘了：

Problem： 

There is no public key available for the following key IDs:
4D270D06F42584E6
You may want to run apt-get update to correct these problems

1. root@debian:/etc/apt# apt-get update
2. Get:1 http://mirrors.163.com stable Release.gpg [386B]
3. Hit http://mirrors.163.com stable Release
4. Ign http://mirrors.163.com stable/main Sources/DiffIndex
5. Hit http://mirrors.163.com stable/main Sources
6. Fetched 1B in 0s (27B/s)
7. Reading package lists... Done
8. W: There is no public key available for the following key IDs:
9. 4D270D06F42584E6
10. W: You may want to run apt-get update to correct these problems

解决的办法为:
apt-get install debian-keyring debian-archive-keyring
然后
apt-key update

1. root@debian:/etc/apt# apt-get install debian-keyring debian-archive-keyring
2. Reading package lists... Done
3. Building dependency tree... Done
4. The following NEW packages will be installed:
5.   debian-keyring
6. The following packages will be upgraded:
7.   debian-archive-keyring
8. 1 upgraded, 1 newly installed, 0 to remove and 266 not upgraded.
9. Need to get 21.1MB of archives.
10. After unpacking 26.0MB of additional disk space will be used.
11. Get:1 http://debian.cn99.com stable/main debian-archive-keyring 2009.01.31 [12.8kB]
12. Get:2 http://debian.cn99.com stable/main debian-keyring 2009.01.18 [21.1MB]
13. Fetched 21.1MB in 7s (2848kB/s)                                                                                                                                
14. (Reading database ... 29393 files and directories currently installed.)
15. Preparing to replace debian-archive-keyring 2007.07.31~etch1 (using .../debian-archive-keyring_2009.01.31_all.deb) ...
16. Unpacking replacement debian-archive-keyring ...
17. Setting up debian-archive-keyring (2009.01.31) ...
18. gpg: key 6070D3A1: "Debian Archive Automatic Signing Key (4.0/etch) " not changed
19. gpg: key ADB11277: "Etch Stable Release Key " not changed
20. gpg: key BBE55AB3: "Debian-Volatile Archive Automatic Signing Key (4.0/etch)" not changed
21. gpg: key F42584E6: public key "Lenny Stable Release Key " imported
22. gpg: key 55BE302B: public key "Debian Archive Automatic Signing Key (5.0/lenny) " imported
23. gpg: key 6D849617: public key "Debian-Volatile Archive Automatic Signing Key (5.0/lenny)" imported
24. gpg: Total number processed: 6
25. gpg:               imported: 3  (RSA: 2)
26. gpg:              unchanged: 3
27. gpg: no ultimately trusted keys found
28.  
29. Selecting previously deselected package debian-keyring.
30. (Reading database ... 29393 files and directories currently installed.)
31. Unpacking debian-keyring (from .../debian-keyring_2009.01.18_all.deb) ...
32. Setting up debian-keyring (2009.01.18) ...
33. root@debian:/etc/apt# apt-key update
34. gpg: key 6070D3A1: "Debian Archive Automatic Signing Key (4.0/etch) " not changed
35. gpg: key ADB11277: "Etch Stable Release Key " not changed
36. gpg: key BBE55AB3: "Debian-Volatile Archive Automatic Signing Key (4.0/etch)" not changed
37. gpg: key F42584E6: "Lenny Stable Release Key " not changed
38. gpg: key 55BE302B: "Debian Archive Automatic Signing Key (5.0/lenny) " not changed
39. gpg: key 6D849617: "Debian-Volatile Archive Automatic Signing Key (5.0/lenny)" not changed
40. gpg: Total number processed: 6
41. gpg:              unchanged: 6

就解决了~

1. root@debian:/etc/apt# apt-get update
2. Get:1 http://debian.cn99.com stable Release.gpg [386B]
3. Hit http://debian.cn99.com stable Release
4. Ign http://debian.cn99.com stable/main Packages/DiffIndex
5. Ign http://debian.cn99.com stable/main Sources/DiffIndex
6. Hit http://debian.cn99.com stable/main Packages
7. Hit http://debian.cn99.com stable/main Sources
8. Fetched 1B in 0s (11B/s)
9. Reading package lists... Done