What is mod_vlimit. “limit the number of simultaneous connections”

Preface

This is the distribution page for the Apache module mod_vlimit.

mod_vlimit allows “Apache HTTP Server” administrators to limit the number of  simultaneous connections(exec cgi php)  from the same IP address or all to any files.

If client accessese are over the limit connections, mod_vlimit return 503 error message to the client.

[warning]
mod_vlimit is for Apache 2.x.
If you use “VirtuaHost”, This is OK.
mod_vlimit is approved Apache module by “Apache Module Registry“.
[/warning]

 

Downloads

mod_vlimit is approved Apaceh module by “Apache Module Registry“.

You can search or browse on “Apache Module Registry“, if you’d like to get the information for mod_vlimit.

[note]

• github[matsumoto-r/mod_vlimit] (if you use git)
• mod_vlimit (on “Apache Module Registry”)

[/note]

Install

On systems that support Apache dynamic shared objects (DSOs), the recommend installation procedure using apxs is:

apxs -i -c mod_vlimit.c

and configured httpd.conf:

LoadModule vlimit_module modules/mod_vlimit.so

 

How to use

limit the number of simultaneous connections per IP address

• set limits to 5 simultaneous connections(cgi php exec) per IP address to the directory(/www/hoge/fuga/)

<Directory "/www/hoge/fuga/">
    VlimitIP 5
</Directory>

• set limits to 3 simultaneous connections(cgi php exec) per IP address to files(test.cgi)

<Files "test.cgi">
    VlimitIP 3
</Files>

• set limits to 4 simultaneous connections(cgi php exec) per IP address to some files(a.cgi b.cgi c.cgi d.cgi …)

<FilesMatch "^*¥.cgi$">
    VlimitIP 4
</FilesMatch>

is equal to:

<Files "a.cgi">
    VlimitIP 4
</Files>
<Files "b.cgi">
    VlimitIP 4
</Files>
<Files "c.cgi">
    VlimitIP 4
</Files>
<Files "d.cgi">
    VlimitIP 4
</Files>
.
.
.
.

• set limits to 1 simultaneous connections(cgi php exec) per IP address to the symlink file(/usr/local/test-cgi/test.cgi -> /var/www/html/test.cgi)

<Files "test.cgi">
    VlimitIP 1 /var/www/html/test.cgi
</Files>

 

limit the number of simultaneous connections per File or Directory

• set limits to 7 simultaneous connections(exec cgi php) to the directory(/www/hoge/fuga/)

<Directory "/www/hoge/fuga/">
    VlimitFile 7
</Directory>

• set limits to 2 simultaneous connections(exec cgi php) to files(test.cgi)

<Files "test.cgi">
    VlimitFile 2
</Files>

• set limits to 5 simultaneous connections(exec cgi php exec) to some files(a.cgi b.cgi c.cgi d.cgi …)

<FilesMatch "^*¥.cgi$">
    VlimitFile 4
</FilesMatch>

is equal to:

<Files "a.cgi">
    VlimitFile 4
</Files>
<Files "b.cgi">
    VlimitFile 4
</Files>
<Files "c.cgi">
    VlimitFile 4
</Files>
<Files "d.cgi">
    VlimitFile 4
</Files>
.
.
.
.

• set limits to 1 simultaneous connections(exec cgi php) to the symlink file(/usr/local/test-cgi/test.cgi -> /var/www/html/test.cgi)

<Files "test.cgi">
    VlimitFile 1 /var/www/html/test.cgi
</Files>

 

logging

mod_vlimit can output some logs. Basically, mod_vlimit don’t output logs but if you “touch” the flag file associated with the log you want, mod_vlimit will output the log.

• Check debug log

touch /tmp/VLIMIT_DEBUG
less /var/log/syslog

• Stop debug log

rm /tmp/VLIMIT_DEBUG

• Check m0dule access log

touch /tmp/VLIMIT_LOG
less /tmp/mod_vlimit.log

• Stop module access log

rm /tmp/VLIMIT_LOG

• module access log sample

[Fri Mar 11 11:54:48 2011] pid=[28734] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 1/5 file_count: 0/0 file=[/var/www/html/32.php]
[Fri Mar 11 11:54:48 2011] pid=[28734] name=[172.16.71.46] client=[172.16.71.46] RESULT: END DEC ip_count: 0/5 file_count: 0/0 file=[/var/www/html/32.php]
[Fri Mar 11 11:54:48 2011] pid=[28648] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 1/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28580] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 2/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28402] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 3/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28532] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 4/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28648] name=[172.16.71.46] client=[172.16.71.46] RESULT: END DEC ip_count: 3/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28776] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 4/5 file_count: 0/0 file=[/var/www/html/33.php]
[Fri Mar 11 11:54:48 2011] pid=[28653] name=[172.16.71.46] client=[172.16.71.46] RESULT:  OK INC ip_count: 5/5 file_count: 0/0 file=[/var/www/html/34.php]
[Fri Mar 11 11:54:48 2011] pid=[28764] name=[172.16.71.46] client=[172.16.71.46] RESULT: 503 INC ip_count: 6/5 file_count: 0/0 file=[/var/www/html/34.php]
[Fri Mar 11 11:54:48 2011] pid=[28544] name=[172.16.71.46] client=[172.16.71.46] RESULT: 503 INC ip_count: 7/5 file_count: 0/0 file=[/var/www/html/34.php]
[Fri Mar 11 11:54:48 2011] pid=[28557] name=[172.16.71.46] client=[172.16.71.46] RESULT: 503 INC ip_count: 8/5 file_count: 0/0 file=[/var/www/html/34.php]
[Fri Mar 11 11:54:48 2011] pid=[28778] name=[172.16.71.46] client=[172.16.71.46] RESULT: 503 INC ip_count: 9/5 file_count: 0/0 file=[/var/www/html/34.php]
[Fri Mar 11 11:54:48 2011] pid=[28580] name=[172.16.71.46] client=[172.16.71.46] RESULT: END DEC ip_count: 8/5 file_count: 0/0 file=[/var/www/html/33.php]

• Check current counter list per files

touch /tmp/VLIMIT_FILE_STAT
cat /tmp/vlimit_file_stat.list

• vlimit_file_stat.list sample

[Fri Mar 11 11:51:15 2011] slot=[2] filename=[20.php] counter=[10]
[Fri Mar 11 11:51:15 2011] slot=[3] filename=[12.php] counter=[7]
[Fri Mar 11 11:51:15 2011] slot=[4] filename=[23.php] counter=[10]
[Fri Mar 11 11:51:15 2011] slot=[5] filename=[24.php] counter=[10]
[Fri Mar 11 11:51:15 2011] slot=[6] filename=[4.php] counter=[2]
[Fri Mar 11 11:51:15 2011] slot=[7] filename=[25.php] counter=[10]
[Fri Mar 11 11:51:15 2011] slot=[8] filename=[2.php] counter=[7]
[Fri Mar 11 11:51:15 2011] slot=[9] filename=[1.php] counter=[5]
[Fri Mar 11 11:51:15 2011] slot=[10] filename=[3.php] counter=[2]
[Fri Mar 11 11:51:15 2011] slot=[11] filename=[5.php] counter=[2]

• Re-create FILE counter lists

rm /tmp/vlimit_file_stat.list
cat /tmp/vlimit_file_stat.list

• Check current counter list per ip

touch /tmp/VLIMIT_IP_STAT
cat /tmp/vlimit_ip_stat.list

• vlimit_ip_stat.list sample

[Fri Mar 11 11:54:29 2011] slot=[0] ipaddress=[172.16.71.46] counter=[6]
[Fri Mar 11 11:54:29 2011] slot=[1] ipaddress=[172.16.71.47] counter=[5]
[Fri Mar 11 11:54:29 2011] slot=[2] ipaddress=[172.16.71.48] counter=[7]
[Fri Mar 11 11:54:29 2011] slot=[3] ipaddress=[172.16.71.40] counter=[3]
[Fri Mar 11 11:54:29 2011] slot=[4] ipaddress=[172.16.71.49] counter=[1]

• Re-create  IP counter lists

rm /tmp/vlimit_ip_stat.list
cat /tmp/vlimit_ip_stat.list