1. Apache Web 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-
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.
9/20/2018
C. Edward Chow

2. Web Server Installation Statistics
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C. Edward Chow

3. Compiling Apache_1.3.12
Download apache_ tar.gz from or closer mirror sites
$tar xzvf apache_ 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.
9/20/2018
C. Edward Chow

4. CS401 Apache Testbed
bilbo.uccs.edu and frodo.uccs.edu are installed with Apache
/mpc/home/www/sites contains the configuration files of various web sites contained in the CD-ROM of Apache text.
See 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.
9/20/2018
C. Edward Chow

5. Apache Exercise Setup
Replace domain name/IP address on 3rd left Linux PC
with bilbo.uccs.edu
sales.butterthlies.com with b2b.uccs.edu
with wait.uccs.edu
Replace domain name/IP address on 4th left Linux PC
with frodo.uccs.edu
sales.butterthlies.com with feline.uccs.edu
with walden.uccs.edu
Replace domain name/IP address on 5th left Linux PC
with gandalf.uccs.edu
sales.butterthlies.com with gallop.uccs.edu
with wind.uccs.edu
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C. Edward Chow

6. Apache Testbed: LAN Setup
/usr/www/lan_setup script for bilbo:
ifconfig eth
ifconfig eth0:
ifconfig eth0:
Or on linuxconf for bilbo, select config | networking | IP aliases for virtual hosts | eth0. Type in , 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).
9/20/2018
C. Edward Chow

7. 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.
9/20/2018
C. Edward Chow

8. 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
9/20/2018
C. Edward Chow

9. 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: ] Server configured -- resuming normal operations or webuser ? 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: ] "GET / HTTP/1.0"
Use a browser (on vinci or other machines) to access the server a few times with url =
“kill `cat <site>/logs/httpd.pid`” to terminate web server. note that it is back quote ` and not ‘
9/20/2018
C. Edward Chow

10. Httpd Configuration File
Apache uses a set of (73) directives to describe to httpd how the web site should be configured.
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
9/20/2018
C. Edward Chow

11. 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 “~”
9/20/2018
C. Edward Chow

12. 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: 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 in httpd -d <server root> or /usr/local/etc/httpd)
9/20/2018
C. Edward Chow

13. 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.
9/20/2018
C. Edward Chow

14. 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 or depending which machine
Check the access_log file. Keep them as record
9/20/2018
C. Edward Chow

15. 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
9/20/2018
C. Edward Chow

16. 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 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
9/20/2018
C. Edward Chow

17. 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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C. Edward Chow

18. Site.Virtual/Name-based
cd /mpc/home/<login>/sites/site.virtual/Name-based
edit the httpd.conf in conf directory:
NameVirtualHost  NameVirtualHost Port 8<last 3 digits of SS#>
<VirtualHost  <VirtualHost bilbo.uccs.edu:portno> Here portno is 8<last 3 digits of your SS#>
ServerAdmin  ServerAdmin
/usr/www  /mpc/home/<login>/sites/
<VirtualHost sales.butterthlies.com>  <VirtualHost sales-bilbo.uccs.edu:portno>
Go to start virtual hositng.
9/20/2018
C. Edward Chow

19. Site.Virtual/IP-based
cd /mpc/home/<login>/sites/site.virtual/IP-based
edit the httpd.conf in conf directory:
Add Port 8<last 3 digits of SS#> right after Group webgroup
<VirtualHost >  <VirtualHost :portno> Here portno is 8<last 3 digits of your SS#>
ServerName bilbo.uccs.edu
ServerAdmin  ServerAdmin
/usr/www  /mpc/home/<login>/sites/
<VirtualHost >  <VirtualHost :portno>
ServerName b2b.uccs.edu
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C. Edward Chow

20. Site.Virtual/Mixed-based
We can mix Name-based with IP-based virtual hosting.
Change “IP-based” to “Mixed-based”. An error in config file.
NameVirtualHost :8888
Port 8888
<VirtualHost bilbo.csnet.uccs.edu:8888>
DocumentRoot /mpc/home/guest/sites/site.virtual/htdocs/customers
<VirtualHost salesbilbo.csnet.uccs.edu:8888>
DocumentRoot /mpc/home/guest/sites/site.virtual/htdocs/salesmen
<VirtualHost :8888>
9/20/2018
C. Edward Chow

21. Port-based Virtual Hosting
Can use one IP address to test many sites.
Change IP-based to Port-based. An error in config file.
Different ports map to different sites.
User webuser
Group webgroup
Listen 7888
Listen 8888
<VirtualHost :7888>
DocumentRoot /mpc/home/guest/sites/site.virtual/htdocs/customers
<VirtualHost :8888>
DocumentRoot /mpc/home/guest/sites/site.virtual/htdocs/salesmen
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C. Edward Chow

22. Bonus Exercise #1
After copying the site.virtual to the nfs mount dir and executing the httpd, the access_log and error_log files are empty.
When use the directory mounted on local disk, there are no problem.
See the bonus exercise on
Try to explain why this happens.
A good answer gets 1 point count towards final grade.
9/20/2018
C. Edward Chow

23. Homework #3 Exercise 2
Run site.virtual/Name-based, site.virtual/IP-based, and site.twocopy according to the textbook and verify the results.
Keep the access_log and error_log as records.
Send me when you finish both exercises.
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C. Edward Chow

24. Homework #3: Problem 3
Explain why it is possible not to require a new IP address to host a customer’s web site, even though it has a unique domain name.
9/20/2018
C. Edward Chow