国外
http://lwn.net/
http://www.tldp.org/
https://rhn.redhat.com
http://www.justlinux.com/
http://www.linuxtoday.com/
http://www.linuxquestions.org/
http://www.fokus.gmd.de/linux/
http://www.linux-tutorial.info/
http://public.www.planetmirror.com/
http://www.freebsdforums.org/forums/
http://www.netfilter.org/documentation/
http://www-106.ibm.com/developerworks/linux/
http://www.redhat.com/docs/ redhat官方文档，redhat用户必看
http://www.redhat.com/apps/support/errata/ redhat安全性警告、软件更新和增强，建议每周至少查阅一次

国内
http://www.fanqiang.com/
http://www.linuxsir.com/
http://www.chinaunix.net/
http://www.linuxfans.org/
http://www.linuxeden.com/
http://www.linuxforum.net/
http://www.linuxaid.com.cn/
http://freesoft.online.sh.cn/
http://www-900.ibm.com/developerWorks/cn/linux/index.shtml
redhat linux下载地址
ftp://ftp.redhat.com/pub/redhat/linux
http://redhat.com/download/mirror.html

redhat 发行版全球官方镜像站
http://freesoft.online.sh.cn 国内高速下载
http://www.linuxeden.com/
http://www.freshrpms.net/
http://www.linux.cz/apt-rpm/ - Red Hat linux 7.x repositories (with all freshrpms included too!)
http://apt-rpm.tuxfamily.org/ - Red Hat linux 6.2, 7.x and 8.0 repositories
http://apt.nlc.no/apt/ - Red Hat linux 6.2, 7.x and Rawhide repositories
http://ftp.uninett.no/pub/linux/apt/ - Red Hat linux 6.2, 7.x, 8.0 and Rawhide repositories
http://redhat.usu.edu/ - Red Hat linux 7.2, 7.3 and 8.0 repositories
ftp://mirror.pa.msu.edu/apt/ - Red Hat linux 7.2, 7.3 and 8.0 repositories
http://apt-rpm.codefactory.se/ - Red Hat linux 7.2, 7.3 and 8.0 and gnomehide repositories
http://apt.42h.de/ - Red Hat Linux 7.2, 7.3 and 8.0 repositories
http://apt.toggletext.com.au/ - A few Red Hat linux 7.2 custom packages
http://people.ecsc.co.uk/~matt/repository.html - Lots of custom Red Hat Linux 8.0 GNOME 2 and related packages
http://ftp-stud.fht-esslingen.de/apt/ - Red Hat linux 7.x, 8.x and rawhide
http://apt.unl.edu/ - Red Hat linux 7.3 and 8.0
http://kde-redhat.sourceforge.net/ - KDE for Red Hat project

linux 常用软件搜索
http://bingle.pku.edu.cn 北大天网ftp搜索，教育网和国内用户查找软件应首先访问，软件特别丰富
http://www.linuxforum.net/ 有很多国外软件的官方镜像，应首先访问
http://rpmfind.net
http://freshmeat.net
http://sourceforge.net
注： 很多软件主站是在sourceforge上的，形如http://phpmyadmin.sourceforge.net的地址，可以通过http: //sourceforge.net/projects/phpmyadmin这样的地址访问，如不能上也可用http镜象直接下载软件如 http://telia.dl.sourceforge.net/phpmyadmin/
http://www.gnu.org GNU的大本营，gcc，bash之类的软件源码可以到这里得到 linux 文档和FAQs
http://www.tldp.org 强烈推荐！ The linux document project: linux HOWTO and guides
http://www.linux.org.tw/CLDP/ 强烈推荐！ TLDP中文版，繁体
http://www.linuxgazette.com/ linux在线杂志
http://linux.tcpip.com.cn/download/ linux中文版文档和软件下载
http://cosoft.org.cn/html/documents/ 很多中文版手册
http://www.google.com 强烈推荐！本站的讨论内容也可以通过google搜索得到，遇到疑难问题到google搜索会得到比绝大多数论坛更快的回答

linux 桌面主站一览表
GNOME: http://www.gnome.org
KDE: http://www.kde.org
XFce: http://www.xfce.org/
Window Maker： http://www.windowmaker.org/
BlackBox: http://sourceforge.net/projects/blackboxwm
XPde: http://www.xpde.com
ROX: http://sourceforge.net/projects/rox
5dwm: http://5dwm.org/
foXdesktop: http://sourceforge.net/projects/foxdesktop
EDE: http://sourceforge.net/projects/ede
UDE: http://sourceforge.net/projects/udeproject

其它OS：
Mandrake linux http://www.mandrakelinux.com
debian linux http://www.debian.org
slackware linux http://www.slackware.com
suse linux http://www.suse.com
FreeBSD http://www.freebsd.org
netbsd http://www.netbsd.org
openbsd http://www.openbsd.org
Solaris http://www.sun.com/solaris 硬件和安装专业站点
linux Kernel内核: http://www.kernel.org
USB安装问题： http://www.linux-usb.org
笔记本计算机安装： http://www.linux-laptop.net
打印机驱动 http://www.linuxprinting.org

主要服务器软件主站
1. WWW server:
Apache http://www.apache.org Apache
SSL模块Mod_ssl http://www.modssl.org
aol server http://www.aolserver.com
2. Servlets/JSP引擎:
Tomcat: http://jakarta.apache.org
Resin: http://www.caucho.com
开源应用服务器AS–Jboss: http://www.jboss.org

3. 服务器语言:
PHP http://www.php.net
Zend http://www.zend.com
Java http://www.javasoft.com
Python http://www.python.org
Zope http://www.zope.org
Perl http://www.perl.org
Ruby http://www.ruby-lang.org/en

4. 数据库:
MySQL http://www.mysql.com
PostgreSQL http://www.postgresql.org
Oracle http://www.oracle.com
sap db http://www.sapdb.org
PHPMyAdmin — http://www.phpmyadmin.org
PHPPgAdmin: http://sourceforge.net/projects/phppgadmin

5. FTP服务器
linux http://ftp.ubuntu.org.cn    (ubuntu ubuntuftp)
wu-ftpd http://www.wu-ftpd.org
Proftpd http://www.proftpd.org
Pure-ftpd http://www.pureftpd.org
ncftpd http://www.ncftpd.com
vsftpd http://vsftpd.beasts.org

6. SMTP服务器
Sendmail http://www.sendmail.org
qmail http://www.qmail.org
Postfix http://www.postfix.org
Exim http://www.exim.org
POP3–qpopper http://www.qpopper.org

7. IMAP服务器
Cyrus-IMAPD http://asg.web.cmu.edu/cyrus/imapd
UW IMAP http://www.washington.edu/imap
courierimap http://www.inter7.com/courierimap

8. 基本安全工具
firewall Iptables: http://www.iptables.org
shorewall: http://www.shorewall.net
inetd Xinetd: http://www.xinetd.org
Openssl: http://www.openssl.org
OpenSSH: http://www.openssh.org
nmap: http://http://www.insecure.org/nmap
Tripwire: http://www.tripwire.org
snort: http://www.snort.org
nessus: http://www.nessus.org
GnuPG: http://www.gnupg.org
chkrootkit: http://www.chkrootkit.org
安全顾问： http://www.cert.org

9. 其它服务器软件
CVS–CVS http://www.cvshome.org
DNS域名解析BIND http://www.isc.org/products/BIND/
DHCP–DHCP http://www.isc.org/products/DHCP/
INN新闻组INN: http://www.isc.org/products/INN/
Proxy代理缓存: Squid http://www.squid-cache.org
Socks代理：http://www.socks.nec.com/
Samba Server: http://www.samba.org
Print CUPS: http://www.cups.org
LDAP OpenLDAP: http://www.openldap.org
流量分析 MRTG http://www.mrtg.org
日志分析 webalizer http://www.mrunix.net/webalizer/
Ipsec/VPN http://www.freeswan.org
路由 Zebra http://www.zebra.org
集群 LVS http://www.linuxvirtualserver.org
MPICH http://www-unix.mcs.anl.gov/mpi/mpich/
PVM：http://www.netlib.org/pvm3/
Rsync: http://rsync.samba.org
linuxconf: http://www.solucorp.qc.ca/linuxconf/
Webmin: http://www.webmin.com