What is a DynHOST used for?
If you use an ISP with ADSL or RTC connection, your IP of connection change at each re-connection.
DynHOST allows you to point your domain or sub-domain to an IP of connection and, if it changes, to update it in real time. In this way, you can host a website on your ADSL line. If you play on line, you can directly communicate your domain name instead of an IP difficult to remember.
Creation of a DynHOST
You just have to request for a DynHOST via the Manager.
Once on this page, add a DynHOST in DNS Zone:
Indicate a sub-domain and a ‘DynHOST’ (IP address)
The creation of this field takes 24 hours
Warning: Your domain must have the following DNS (or hosts using the IP of the following DNS):
If you would like to host pages on your machine, you must obviously have Apache on your machine.
These identifiers enable you to update the IP of the DynHOST using a software external to OVH (see below).
An identifier enables to manage one or all DynHOST sub-domain(s) that you have created. It is made of the domain, followed by the name you want, i.e.: domainname.com-ident.
At the time of the addition of a new DynHOST, an option to tick allows you to create an identifier directly after validation of the creation.
You can manage them via the Manager.
Once on this page, you will be able to manage your identifiers (creation, modification, password and deletion)
Tools to use
Next, you just have to download a software of IP management:
(Do not take into account the possible error in return)
For this script, look for the following section:
Updatehost = “members.dyndns.org”
Updatepage = “/nic/update”
Useragent = “ipcheck/” + Version
And replace Updatedhost = “members.dyndns.org” by www.ovh.co.uk
Then, you will just have to set this software with your DynHost? identifier and its password.
Examples of use
Set this small software with your DynHOST identifier and its password.
user/pass: DynHOST identifier & password
update your IP for these hosts: dns.domainname.com (DynHOST field that you have created from your manager)
For further information: Consult faq section of the software
Untick “Desactivated/ignore this account”
DNS service: Select OVH.com
Detection of IP: select ‘Detection of IP by default”
User name: your DynHOST identifier
Password: the password associated to your Identifier
Domain/host: the sub-domain for which you have defined a field of “DynHOST” type in the Manager.
What do you need to have?
Installation of scripts:
The archive contains the following files:
Unzip the archive in the directory of your choice and edit the dynhost file to include your settings:
Check as well that the dynhost script has the right authorizations of execution for your user. Any operation carried out by the script are saved in a dynhost.log file.
It is in case of traditional use. Your computer uses Linux, it manages the connection and is connected to an Apache server. You just have to execute the dynhost script. This one recovers the IP address of the network interface used by the internet connection (ppp0 by default), then it compares it with the address previously updated (stored in the old.ip file). If the address has been correctly modified, it calls the ipcheck.py script to update your DynHOST field with this address,
The use is the same one as above. However, the dynhost script does not recover the IP address but uses the one you specified. To do so, you just have to specify ‘-a10.0.0.10’ option in OPTIONS section where 10.0.0.10 represents the IP address with the one your DynHOST field must be updated. It is a static IP, this method is not appropriate if your ISP provides a dynamic IP.
It is in case you use a personal router behind which you have a WEB server. The ipcheck.py script allows you to update the DynHOST field with public IP address of the router. This is possible if your router provides a WEB interface of administration. To do so, you have to specify the option “-rhttp:/192.168.0.1/Status.php” in OPTIONS section. 192.168.0.1 is the address used to obtain WEB interface and Status.php is the page on which is the public IP address of the router.
Warning: It does not regulate the configuration of the specific Fowarding Port proper to each router! With this option, the script will request from you to enter the password necessary to access to the WEB interface.
Installation in crontab for periodical execution
This handling enables you to indicate to your system that it must restart periodically the dynhost script. In that way, your DynHOST field has more probability of being up to date if your ISP regularly forces you to change the IP address.
The frequency on which the script is executed depends on your use, you may set it up to be executed once a day, every hour…..
The content of the crontab change by executing the following command:
This file edit itself in the same way as a Vi editor (key i to insert, -ESC- then :wq to save and quit).
Add one of the following lines in the file, according to your needs:
101**/home/user/dynHost/dynhost (every 1st of the month at 00:01)
10**0 /home/user/dynHost/dynhost (every Sunday at 00:01)
10*** /home/user/dynHost/dynhost (every day at 00:01)
1**** /home/user/dynHost/dynhost (every hour)
/home/user/dynHost/dynhost represents obviously the complete way to the dynhost script.
You can check the content of your crontab by executing this command:
Bash-2.05b$ crontab -1
More info about crontab here
Tips if you have many DynHost
If you have several
A CNAME allows to redirect a field to another address. For example, you have 3 domains: domainA.com, domainB.com and domainC.com
these 3 domains have a
They all point to the same Ip
At each modification of this Ip address, you must update these 3 fields.
By using a CNAME, only one field will have to be updated (the one of your choice).
You must keep one
To sum up:
forum.domainB.com becomes a CNAME of forum.domainA.com
megaforum.domainC.com becomes a CNAME of forum.domainA.com
Once forum.domainA.com is updated, forum.domainB.com and megaforum.domainC.com are automatically updated.
Finally, you will have:
forum.domainA.com, which is a
forum.domainB.com, which is a CNAME to forum.domainA.com
megaforum.domainC.com, which is a CNAME to forum.domainA.com