Is DDNS Valid or Do We Have to Have a Static IP for VPN?

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raezorblaedz - 28 Nov 2006 19:23 GMT

When I called both hughesnet (sattelite service) they said running a VPN
wasn't possible because the signal terminates in the sattelite modem (192.168.
0.1).
When I called & chatted with LinkSys' poor support they didn't know what DDNS
was.
Is DDNS (dyndns.org) a valid replacement for a static IP or do we have to
have a Static IP for VPN?

Thanks for any assistance in advance,
John

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Sooner Al [MVP] - 28 Nov 2006 21:51 GMT

Well, I use No-IP.com (a dynamic naming service like DyDNS) to access my
home LAN via a VPN (PPTP or OpenVPN) or SSH tunnel all the time. I happen to
be on a cable ISP.

The issue you may have is forwarding/opening the appropriate ports, ie. for
PPTP VPN you need TCP Port 1723 and have GRE Protocol 47 traffic enabled,
through any firewall/router to your VPN server. Will Hughsnet forward/open
those for you?

Latency may also be an issue because of the up/down time on the satellite
link. I have no experience with that.

Signature

Al Jarvi (MS-MVP Windows Networking)

Please post *ALL* questions and replies to the news group for the
mutual benefit of all of us...
The MS-MVP Program - http://mvp.support.microsoft.com
This posting is provided "AS IS" with no warranties, and confers no
rights...

> When I called both hughesnet (sattelite service) they said running a VPN
> wasn't possible because the signal terminates in the sattelite modem
[quoted text clipped - 8 lines]
> Thanks for any assistance in advance,
> John

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raezorblaedz - 28 Nov 2006 22:11 GMT

Sooner Al,

Thank you for your response.

you use no-ip.com, for what? to assign a DDNS in replacement of Static IP?
You seem to know what you are talking about and I feel stupid, no longer
ignorant about this. The 1723 is open (I beleive), and I have selected to
open all vpn PPTP,IPSec,L2TP Passthroughs.

1723 opening valid?
Application: VPN
Start: 1723
End: 1723
Protocol: TCP
IP Address: 10.xxx.xxx.100 (my pc)
Enabled: Selected

thanks,
John

>Well, I use No-IP.com (a dynamic naming service like DyDNS) to access my
>home LAN via a VPN (PPTP or OpenVPN) or SSH tunnel all the time. I happen to
[quoted text clipped - 13 lines]
>> Thanks for any assistance in advance,
>> John

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Sooner Al [MVP] - 29 Nov 2006 22:09 GMT

No-IP.com, or DynDNS or other similar services, allow you to call a server
if the server is assigned a dynamic IP (DHCP assigned) by your ISP. It is
completely different from a static IP that you would configure to a server
or workstation on a LAN.

In my case I assign a static IP to my home test PPTP VPN server. My ISP, Cox
HSI, in turn assigns me a DHCP IP address. I use No-IP.com to map a Fully
Qualified Domain Name (FQDN), or alias if you will, to my ISP's DHCP IP
address. So the way it works is like this...

I install a small program on one of my desktop PCs. The program contacts the
No-IP.com servers on a time scheduled basis. The servers then know my
current IP, as assigned by my ISP, and map the address to my FQDN.

I port forward TCP Port 1723 through my router to the static IP of my PPTP
VPN server on my home LAN. I also make sure PPTP Pass Through is enabled on
the router, which is either a Linksys BEFSR41 (v1) or a NR041 depending on
my current LAN configuration. I call my PPTP VPN server from a remote site
using the FQDN (or alias) from No-IP.com.

Here is how I have my XP PPTP VPN server configured. Ignore the PocketPC
sections and use a *STRONG PASSWORD*...

http://theillustratednetwork.mvps.org/WM2003/WM2003PPTPVPN.html

This is based on this example LAN...

http://theillustratednetwork.mvps.org/WM2003/PPTP_VPN/LAN/PPTPExampleLAN.html

In your case you need to disable IPSec and L2TP Pass Through since they are
not needed.

Make sure you also configure the XP SP2 Windows Firewall for PPTP VPN if its
running on your XP PPTP server PC. Note the XP SP2 Windows Firewall
automatically passes GRE Protocol 47 traffic when TCP Port 1723 is
forwarded/opened.

You can test this using the "PPTP Ping" and "VPN Traffic" sections detailed
on this page...

http://www.microsoft.com/technet/community/columns/cableguy/cg0105.mspx

What Linksys router do you have? That information may help others help
you...

Signature

> Sooner Al,
>
[quoted text clipped - 35 lines]
>>> Thanks for any assistance in advance,
>>> John

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