When you use a cable or DSL modem, the WL500 usually doesn't know its external IP address. This is a problem for the built-in DynDNS client (accessible through the web pages), because that client requires the address for updating DynDNS.

Luckily, DynDNS provides an alternative solution that does work and it's called inadyn. This page describes how to use inadyn for updating your DynDNS record.

You will need ipkg for installing it (see http://www.sprayfly.com/wiki/Ipkg), but otherwise it's pretty straightforward.

Download inadyn from the unslung library using ipkg.

[admin@asus root]$ ipkg install inadyn

For your reference, my ipkg configuration file (/opt/etc/ipkg.conf) looks as follows:

Code:
src wl500g http://wl500g.dyndns.org/ipkg
src unslung http://ipkg.nslu2-linux.org/feeds/unslung/wl500g
dest root /opt
Note that /opt is my USB harddisk.

The result can be shown by:

Code:
[admin@asus root]$ ipkg files inadyn
Package inadyn (1.96.2-1) is installed on root and has the following files:
/opt/man/man5/inadyn.conf.5
/opt/bin/inadyn
/opt/share/doc/inadyn/readme.html
/opt/man/man8/inadyn.8
Successfully terminated.
Create a configuration file /opt/etc/inadyn.conf

Code:
username yourusername
password yourpassword
alias whatever.you.use.com
background  # run in background mode
syslog  # Log to syslog
update_period_sec 1600  # Check every x seconds
Add the executable to the end of a startup script (one that is executed after the drive is mounted). I added the following line to /usr/local/sbin/post-mount:

Code:
/opt/bin/inadyn --input_file /opt/etc/inadyn.conf
Save the script:

Code:
flashfs save
flashfs commit
That's it.