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Thursday, February 4, 2010

DD-WRT Web Server

DD-WRT runs a small httpd server used for configuring the router. This guide will show how to use it to serve you own pages to your LAN or to the world. Please remember that opening WEB server to the world could be potential security problem.

Assumptions
- You have telnet and SSH enabled on your router. See Telnet/SSH_and_the_Command_Line.
- You can send files via SSH to and from your desktop (e.g with WinSCP)
- You have jffs enabled and enough free space to store your files or you have working mmc mod.
- I will assume you are installing to the jffs partition. If you are not, replace jffs with mmc or some other folder
- You have the "Enable Info Site" enabled (Administration -> Management -> WEB Access)
- Optional: you have the "Wireless GUI Access" enabled (Wireless -> Advanced Settings)
- You MUST name your index file Info.htm (note upper case "I", thus "Info.htm" and NOT "info.htm")

How will this work?
- We will move the router's web admin to port 81
- We will start your WEB server at port 80
- Optional: we will open port 80 to the world

Procedure
1) Copy your files to the router, i.e. to the /jffs folder
2) Open web admin Administration -> Diagnostics, press "Run"
3) Enter these lines to the Commands field:

killall httpd
cd /www
httpd -p 81 -h /www
cd /jffs
httpd -h /jffs
4) Press "Save Startup", the router will reboot or reboot it manually.


Optional: open to the world

1) Open web admin Administration -> Diagnostics, press "Run"
2) Enter this line to the Commands field:
/usr/sbin/iptables -I INPUT 1 -p tcp --dport 80 -j logaccept
3) Press "Save Firewall", the router will reboot or reboot it manually.
Congratulations!!!, you have your own web server running.

Please remember your router's config pages are now at 192.168.1.1:81
This method of changing the admin port will make remote web admin inoperable. A better way is to set the http_lanport nvram variable instead.

How to cancel this?

Telnet to the router and type:

nvram set rc_startup=""
nvram set rc_firewall=""
nvram commit
reboot

How to access/edit pages
I.
You can add your own pages to /tmp/www folder and then access them with http://192.168.1.1/user/Yourpage.asp
Only static html pages, but if you need dynamic pages you can use CGI scripts (sh scripts or some binary file)
Create the directory /tmp/www/cgi-bin
Then create a script like:

#!/bin/sh
echo "<html><body>hello world</body></html>"
Save your script as script.cgi and
chmod +x /tmp/www/cgi-bin/script.cgi
You can execute the page going to http://192.168.1.1/user/cgi-bin/script.cgi
Reference: this thread
II.
Shellscripts with .sh will work in folder /tmp/www/cgi-bin as well...
example would be:
#!/bin/sh
echo '<HTML><HEAD><TITLE>Custom Script Test</TITLE></HEAD>'
echo '<BODY>'
nvram get router_name
echo ' sample custom script:<br>'

NOW=`date +%s`

echo "Unix-Time here on this device is ${NOW}. Nothing usefull...<br>"
echo "Just a test..."
save this as
/tmp/www/cgi-bin/custom.sh
and make it executable:
chmod +x /tmp/www/cgi-bin/custom.sh
and point your browser to it:
http://ROUTER.IP.HERE/user/cgi-bin/custom.sh
and you should see the generated output...
This is tested with
DD-WRT v24-sp2 (10/22/08) mega - build 10564M NEWD Eko

Note: In these examples, we created scripts in the /tmp directory which is actually pointing to SDRAM. Any pages or scripts in this directory will be lost upon router reboot and/or power loss, unless you back them up first in jffs2/mmc/nvram.

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