Web Apache Server
A PAtCHy server: developed by the Apache group formed 2/95 around a number of people who provided patch files for NCSA httpd 1.3 by Rob McCool. History-http://www.apache.org/ABOUT_APACHE.html First official public release (0.6.2) in April 1995 Add adaptive pre-fork child processes (very important!). Modular structure and API for extensibility (Bob Thau) Port to multiple platforms. Add documentation. Apache 1.0 was released on 12/1/95. Pass NCSA httpd to be #1 server in Internet.
04/21/09 C. Edward Chow CS4 01 Pag
Web Server Installation Statistics
http://www.netcraft.co.uk/survey/
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CS4 01 Pag
Compiling Apache_1.3.12
Download apache_1.3.12.tar.gz from http://www.apache.org/dist or closer mirror sites $tar xzvf apache_1.3.12.tar.gz $ ./configure --prefix=PREFIX $ make $ make install $ PREFIX/bin/apachectl start Here PREFIX is the prefix of the directory containing the distribution, typically it is /usr/local/apache.
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C. Edward Chow
CS401 Apache Testbed
bilbo.uccs.edu and frodo.uccs.edu are installed with Apache1.3.12. /mpc/home/www/sites contains the configuration files of various web sites contained in the CD-ROM of Apache text. See http://cs.uccs.edu/~cs401/cs401lab.html for more detail on how to carry out the exercise. Copy /mpc/home/www/sites to your directory. To avoid conflict, use port # = 8<last 3 digits of SS#> Add "Port 8<last 3 digits of SS#>" to httpd.conf.
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Apache Exercise Setup
Replace domain name/IP address on 3rd left Linux PC
www.butterhlies.com 192.168.123.2 with bilbo.uccs.edu 128.198.192.182 sales.butterthlies.com 192.168.123.3 with b2b.uccs.edu 128.198.192.172 www.faraway.com 192.168.124.1 with wait.uccs.edu 128.198.192.202
Replace domain name/IP address on 4th left Linux PC
www.butterhlies.com 192.168.123.2 with frodo.uccs.edu 128.198.192.183 sales.butterthlies.com 192.168.123.3 with feline.uccs.edu 128.198.192.173 www.faraway.com 192.168.124.1 with walden.uccs.edu 128.198.192.203
Replace domain name/IP address on 5th left Linux PC
www.butterhlies.com 192.168.123.2 with gandalf.uccs.edu 128.198.192.194 sales.butterthlies.com 192.168.123.3 with gallop.uccs.edu 128.198.192.174 www.faraway.com 192.168.124.1 with wind.uccs.edu 128.198.192.204
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C. Edward Chow
Apache Testbed: LAN Setup
/usr/www/lan_setup script for bilbo: ifconfig eth0 128.198.192.182 ifconfig eth0:0 128.198.192.172 ifconfig eth0:1 128.198.192.202 Or on linuxconf for bilbo, select config | networking | IP aliases for virtual hosts | eth0. Type in 128.198.192.172, 128.198.192.202 for IP aliases (I have not succeeded in using the above method.) Normally we skip lan_setup. We will share the same lan_setup. Run the above lan_setup if you find the computer is configured incorrectly (through ifconfig).
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C. Edward Chow
Ifconfig command
Interface configuration command. There is an equivalent command ipconfig on win32. In Redhat linux, it is in /sbin. I have modified /etc/profile to include that directory in $PATH. Use ifconfig to show the status Use ifconfig eth0:1 down to shut down the IP aliase. Use ifconfig eth0:1 up to bring it up again.
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C. Edward Chow
CS4 01 Pag
Apache Web Site Exercises
Each site.<exercise> directory contains conf: configuration files, httpd.conf, srm.conf, access.conf, mime.types htdocs: contains web pages, scripts logs: access_log, error_log, httpd.pid, (referer_log, agent_log) go: alias of "httpd -d xxSITESxx/site.<name> -X" -d for the site directory, -X single process execution Edit the httpd.conf file. Add the following lines Port 8<last 3 digits of your SS#> TransferLog /mpc/home/<login>/sites/site.<name>/logs/access_log In go shell script file, replace xxSITESxx with /mpc/home/<login>/sites replace <name> with the corresponding site name. Type go to start the web server
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04/21/09
C. Edward Chow
Examine httpd Configuration
To enhance the security, webuser is created to run httpd Add "User webuser" and "Group webgroup" to httpd.conf. "tail -f <site>/logs/error_log" or "ps aux | grep webuser" to see if the server is configured and running.
[Sat Feb 7 20:23:57 1998] Server configured -- resuming normal operations or webuser 13013 0.0 2.2 1260 704 ? S 20:23 0:00 httpd -d /home/cs401
"tail -f <site>/logs/access_log" to see the processing results of client requests
usrp16.uccs.edu - - [07/Feb/1998:03:21:16 -0700] "GET / HTTP/1.0" 200 170
Use a browser (on vinci or other machines) to access the server a few times with url = http://bilbo:8345/ "kill `cat <site>/logs/httpd.pid`" to terminate web server. note that it is back quote ` and not `
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Httpd Configuration File
Apache uses a set of (73) directives to describe to httpd how the web site should be configured.
http://www.apache.org/docs/mod/directives.html Each Apache configuration directive is described using a common format that looks like this: Syntax: directive-name some args Default: directive-name default-value Context: context-list Override: override Status: status Module: module-name Compatibility: compatibility notes
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Block Directives
Directives that limit the application of other directives. Specify by a group like a tag section in html. <VirtualHost host[:port]> ... </VirtualHost> <VirtualHost...><Directory dir>, <Files file>, <Location URL> in ascending order of authority. <Location> can overwrite others. dir, file, URL can specify using wildcards and full regular expressions preceded by "~"
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List of Directives
User, Group: specify user and group that httpd runs on. ServerName: hostname of server (for redirection URL) ResourceConfig, AccessConfig: for reading additional related directives. Can be disabled by /dev/null as value Port: specify the port httpd run on ServerAdmin:email addr. for browser to do automatic replies. DocumentRoot: TransferLog, ErrorLog, PidFile: where access,error logs, httpd.pid should be located. Can be file or pipe "|rotatelogs" The file is relative to the server root directory
(specified httpd in -d <server root> or /usr/local/etc/httpd)
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Directives
KeepAlive [on|off](on): keep connection alive for n requests before terminate provided they come in before timeout. n is defined in MaxKeepAliveRequests <n>(100) directive KeepAliveTimeout <n>(15): wait for the next request for n seconds before terminate the connections. Timeout <n>(300): max. time in sec for a block data. HostNameLookups [on|off|double](off): do reverse DNS lookup for logging the domain name of the request. MaxClients <n>(256): the limit of # of simultaneous requests (hence the # of child processes). MaxRequestsPerChild <n>(0): Spare(child) server dies after <n> requests, avoid mem leak. 0 mean infinite requests. Min/MaxSpareServers <n>(5/10): # of Idle child servers StartServers <n>(5): sets the number of child server processes created on startup. CS4
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04/21/09
Homework#3 Exercise 1: Site.toddle and Site.simple
"cp -r /mpc/home/www/sites /mpc/home/<login>" Edit the httpd.conf in conf directory DocumentRoot /usr/www/site.simple/htdocs DocumentRoot /mpc/home/<login>/sites/site.simple/htdocs Port 8<last 3 digits of your SS#> TransferLog logs/access_log Edit go shell script "httpd -d /mpc/home/<login>/sites/site.<name> [-X]" go in the site.simple does not have X. go will start the web server. Control-c will terminate it. Use browser to visit the site a few times. Remember to specify the port # in url. For IE browser, type http://bilbo.uccs.edu:<portno>/ or http://frodo.uccs.edu:<portno>/ depending which machine CS4 Check the access_log file. Keep them as record 01
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Homework#3 Exercise 1
User webuser Group webgroup ServerName bilbo.uccs.edu or frodo.uccs.edu DocumentRoot /mpc/home/<login>/sites/site.toddle/htdocs Port 8<last 3 digits of your SS#> TransferLog logs/access_log
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C. Edward Chow
CS4 01 Pag
Site.twocopy
Create two web servers: one serves customers; one for sales. There are two directories in site.twocopy. In customers/conf/httpd.conf, replace www.butterthlies.com with bilbo.uccs.edu add Port 8<last 3 digits of SS#> Here BindAddress is used to specify the reception of request from specific IP address (domain name) by this web server. BindAddress bilbo.uccs.edu In sales/conf/httpd.conf replace sales.butterthlies.com with b2b.uccs.edu Replace Listen sales.butterthlies.com:80 with Listen b2b.uccs.edu:8<last 3 digits of SS#> httpd -d /mpc/home/<login>/sites/site.twocopy/customers -X httpd -d /mpc/home/<login>/sites/site.twocopy/sales -X CS4
C. Edward Chow 01 Pag
04/21/09
Web Hosting
Named-based vs. IP-based Virtual Host (VH) HOST: <name> a unique IP address for each VH on metaheader different to support a lot of VHs old browsers not support this Use <VirtualHost hostname[:port]> block directives Specify ServerAdmin, DocumentRoot, ServerName, ErrorLog, TransferLog for individual VH Be aware that UNIX File Limits on # of file descriptors. (default 64) only support 32 VHs? You may want to increase # of child servers.
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Site.Virtual/Name-based
cd /mpc/home/<login>/sites/site.virtual/Name-based edit the httpd.conf in conf directory: NameVirtualHost 192.168.123.2 NameVirtualHost 128.198.192.182 Port 8<last 3 digits of SS#> <VirtualHost www.butterthlies.com> <VirtualHost bilbo.uccs.edu:portno> Here portno is 8<last 3 digits of your SS#> ServerAdmin [e-mail] ServerAdmin <login>@cs.uccs.edu /usr/www /mpc/home/<login>/sites/ <VirtualHost sales.butterthlies.com> <VirtualHost sales-bilbo.uccs.edu:portno>...