Please Help DDNS

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Please Help DDNS

22
5
NAS
DS218+
Operating system
  1. macOS
Mobile operating system
  1. iOS
Hi everybody,
I am new to the forum and I was wondering if somebody could help me with VPN-DDNS.
The DDNS has been set up correctly, I can prove it because the DNS server is using my DDNS. The only problem am having is the DDNS working with the VPN (OpenVPN or L2TP).
The VPN works well with my External Address (IPv4) but it won't work with my DDNS. Please see the Screenshots any help will be much appreciated
 

Attachments

  • Connected with External Address (IPv4).png
    Connected with External Address (IPv4).png
    5.8 MB · Views: 78
  • Normal connection with External Address (IPv4).png
    Normal connection with External Address (IPv4).png
    3.2 MB · Views: 73
  • Will Not Connect with DDNS.png
    Will Not Connect with DDNS.png
    5.8 MB · Views: 75
Have you tested this while not being inside your LAN? This could be that your router has no NAT loopback features so it cant internaly resolve the DDNS name that points to the device that is inside your LAN (while you are in that LAN as well).

Try and test access outside your LAN (over 4G) and see if that will work. Port forward is not a problem if it works with a public IP, as well as a firewall, so its likely a dns resolution problem.
 
The DDNS works well on my Network or outside my network, unfortunately, it won't work with VPNs (openVPN or L2TP).
 
If I used my DDNS (dp.synology.me 1194) on the remote server, the VPN won't work but if use my external IP address example:: remote 80.23.151.301 1194 it does work. Outside my network, I can use a 4G and am able to access the NAS with a DDNS address. As I said the DDNS works fine only it does not work with the VPNs
 
The DDNS works well on my Network or outside my network, unfortunately, it won't work with VPNs (openVPN or L2TP).
Hi,

It doesn’t make sense. The D(DNS) will point to your public IP address, what happens after that is between the client and the host.
Unless I didn’t understand the problem, your issue should be a messed up configuration somewhere.
 
You’re absolutely right, somewhere on the configuration between the DDNS and the VPN, needs to be fixed unfortunately i don’t know what it is.
Actually the ddns is pointing correctly to my public IP address but if the ddns is used on a vpn it doesn’t work. My VPNs work only with the public IP address, very strange indeed
 
L2TP IPsec not working with a DDNS resolved IP address is odd, when the same IP address does work. But OpenVPN does have the configuration setting to allow or not using any or just a specific name (or if not a name then an IP address) as @Telos asked.

Can you share the contents of your .ovpn file, with the private details obscured. e.g.
  • AA.BB.CC.DD for an IP address
  • my.ddns.domain.tld for a server name
  • PP for port number
  • and just remove the certificate information between the certificate tags.
 
Last edited:
L2TP IPsec not working with a DDNS resolved IP address is odd, when the same IP address does work. But OpenVPN does have the configuration setting to allow or not using any or just a specific name (or if not a name then an IP address) as @Telos asked.

Can you share the contents of your .ovpn file, with the private details obscured. e.g.
  • AA.BB.CC.DD for an IP address
  • my.ddns.domain.tld for a server name
  • PP for port number
  • and just remove the certificate information between the certificate tags.


openVPN file
PP for port number 1194
________________________________________


dev tun
tls-client

remote domip.synology.me 1194

# The "float" tells OpenVPN to accept authenticated packets from any address,
# not only the address which was specified in the --remote option.
# This is useful when you are connecting to a peer which holds a dynamic address
# such as a dial-in user or DHCP client.
# (Please refer to the manual of OpenVPN for more information.)

#float

# If redirect-gateway is enabled, the client will redirect it's
# default network gateway through the VPN.
# It means the VPN connection will firstly connect to the VPN Server
# and then to the internet.
# (Please refer to the manual of OpenVPN for more information.)

#redirect-gateway def1

# dhcp-option DNS: To set primary domain name server address.
# Repeat this option to set secondary DNS server addresses.

#dhcp-option DNS DNS_IP_ADDRESS

pull

# If you want to connect by Server's IPv6 address, you should use
# "proto udp6" in UDP mode or "proto tcp6-client" in TCP mode
proto udp

script-security 2


comp-lzo

reneg-sec 0

cipher AES-256-CBC

auth SHA512

auth-user-pass
<ca>
 

Attachments

  • Connected with my Public Address.png
    Connected with my Public Address.png
    5.8 MB · Views: 18
openVPN file.......
That looks ok to me. I use a personal domain but still with DDNS updating.

The only differences to my DSM OpenVPN configuration (I also have OpenVPN service on the router) is that I uncommented redirect-gateway def1 and added dhcp-option DOMAIN local.domain.tld because I have a local DNS server and and a lazy typer.

That leaves the very odd situation that, from the Internet, domain based access to VPN services fail to resolve yet IP access works. Then add that domain based access to web services work.

I would definitely try with the iPhone on mobile data, and the Mac using the iPhone as hotspot.

Are you running any other services or background applications on the Mac that may be interfering with OpenVPN?
 
Many thanks, guys for putting a smile back on me. Problem solved by using the OpenVPN server on another computer,
I have also tried using my iPhone on mobile data, and the Mac using the iPhone as a hotspot ( thanks to user Fredbert) "boom". Now the DDNS works faultlessly.
Happy Halloween to you all
 

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