DynDns is one of the free(as in no cost) Dynamic DNS provider.A Dynamic Dns is a service that permit you to have your own address name (such as rails.homelinux.org/) so you can offer services such as SSH or web server(http://rails.homelinux.org/) while having a Dynamic ip...
 The setup
- updatedd: updatedd-wrapper doesn't have a rc.d mode so you need to create it yourseld
- ipcheck : doesn't work for me because it doesn't find my ip on my userspace pppoe interface(tun0)
- ddclient: comes with a rc.d script...that's the good one
It would be nice if the ppp daemon could call script when the ip changes...but as i don't know how to do it we will use the daemon mode of ddclient.
run this command in order to install ddclient:
cd /usr/ports/dns/ddclient && make config && make install
then you need to configure it: here's my config file:
daemon=1 # check every 300 seconds syslog=yes # log update msgs to syslog mail=root # mail all msgs to root mail-failure=root # mail failed update msgs to root pid=/var/run/ddclient.pid # record PID in file. ssl=yes # use ssl-support. Works with ssl-library login=GNUtoo # default login password=mypassword # default password #mx=mx.for.your.host # default MX #backupmx=yes|no # host is primary MX? #wildcard=yes|no # add wildcard CNAME? custom=yes, \ server=members.dyndns.org, \ protocol=dyndns2 \ gnutoo.homelinux.org
you can do your own copying the sample file to /usr/local/etc/:
cp /usr/local/etc/ddclient.conf.sample /usr/local/etc/ddclient.conf
and then editing it...
then we will need to execute the script when the internet comes up: add this to /etc/rc.conf:
then if you get insternet via ppp,pppoe,pppoa: create the ppp.linkup file with the following content:
alice: !bg /usr/local/etc/rc.d/ddclient restart
change alice to match the provider you defined in /etc/ppp.conf
BE CAREFULL...you have to wait some time between the time the internet comes up and ddclient is restarted
 List of Dynamic DNS Providers
The following is a list of Dynamic DNS solution providers that support open source operating systems:
Many of these services offer free dynamic-IP name resolution using pre-defined domain names as well as paid-for services allowing the use of personal (self registered) domain names. For example No-IP has a domain name of 'servebeer.com' that can host sub-domains for free such as 'mykillerwebsiteproject.servebeer.com'. The paid-for service allows the use of your own domain name such as 'www.mykillerwebsiteproject.com'.
 See Also
The open source firewall project called SmoothWall has in-built support for the leading Dynamic DNS providers.