Remote Access VPN with Dynamic IP - DDNS

Unanswered Question
Feb 3rd, 2010

Hi all!

I need to configure Remote Access VPN on a router 1751. But this router receives dynamic IP of the provider. I know to configure static IP, but do not know for dynamic IP. I have heard that have to set up DDNS on the router, and clients connect to the vpn server (1751) through the url and not of the IP.

Could anyone help me?

Attach topology.


I have this problem too.
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Farrukh Haroon Mon, 02/08/2010 - 06:19

AFAIK, at least one side of the VPN needs to have a static IP Address. Both sides cannot be dynamic.



JORGE RODRIGUEZ Mon, 02/08/2010 - 11:38

Agree with  Farrukh's , in addition to his comment ,  you may be able to work around it on the DSL router dynamic IP side  by implementing some sort of dynamic DNS updates ,  there are freeware dynamic DNS updaters software outthere you can run on a host on the inside of your  OFFICE network , have that utility update your dynamic public  IP against public DNS thus providing constant update of  your public IP for a DNS name of your choice .

This is how it works:

1- Run a directupdate client in a host on the inside your OFFICE network, there are freeware ones out there , but you can use one for small cost of $25.00 or a bit more  from this site     allows for software updates and  tech support,

2- Do a search for free Dynamic DNS services  and opene an account  here is a good list  .  Use a legit service for small yearly fee   , here is one I have used for 5 years with no issues   for $15.00  yearly fee

3-  Install the directupdate client to a host on the inside ,  which you will configured with information as the router's inside interface IP password  etc..  as well as provide directupdate client software with  dyndns account information where directupdate client  will update  the public  DNS IP  if your router's public IP address changes

DNS names of preference depends on the service you chose and varies from dynamic dns service providers  where you may be able to make your own DNS name or they will pick one for you.

That's prety much it , I have tested this on 1841  series router, PIX506  and ASA5505 firewalls using    Dynamic to Static L2L and RA VPN worked great,  Im sure will work for you.




chris-hart Tue, 02/09/2010 - 00:46

I have sucessfully configured a 1760 router exactly like this, it allows remote access from PC's that have the Cisco VPN client installed.  First thing I did was to configure the router for DSL operation with NAT, once that was tested and working I then configured DDNS using the DynDNS service, its free and reliable,  once this was tested and working I then configured the VPN service, it works really well and is an ideal solution for small businesses to allow staff access to there services.  The only downside is that you have to use the Domain Name that is allocated by the DynDNS account but you do have some options to choose from.  


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