VPN Ports Closed - VPN Timeout

Question

Trying to setup VPN on RBR50 router connected to SB1683 cable modem. Testing VPN connection on OpenVPN IOS via cellular. Public IP matches that of router settings. Every time testing the VPN it times out because there is no response.

The ports appear closed when using online checkers but there are no apparent firewall settings on either router or modem or blocking from ISP (Xfinity). No-IP DDNS that confirmed through editing and it reloading back to known IP. Logs follow this loop:

[Nov 14, 2025, 14:53:40] Contacting x.x.x.x:12973 via UDP

[Nov 14, 2025, 14:53:40] EVENT: WAIT

[Nov 14, 2025, 14:53:40] Connecting to [all.ddnskey.com]:12973 (x.x.x.x) via UDP

[Nov 14, 2025, 14:53:50] Server poll timeout, trying next remote entry...

[Nov 14, 2025, 14:53:50] EVENT: RECONNECTING

[Nov 14, 2025, 14:53:50] EVENT: RESOLVE

Any ideas before I factory reset or find another vpn solution? At a total loss.

CrimpOn · Answer

Could you please edit the configuration file and change this line:
verb 0
to
verb 5
This will provide a more detailed log file.

StephenB · Answer

5_D wrote:
Xfinity

Is the router public IP address in the range of 100.64.0.0 to 100.127.255.255?
&nbsp;
If so, then Xfinity has changed your public IP to use carrier-grade NAT.
&nbsp;

5_D · Answer

No

5_D · Answer

The smartphone config file already had verb 5. I tried with windows via Verizon hotspot. I had to edit the config for tun and remove lines for it to work. I have tried rebooting after changing: IPv6, UPnP, port #, traffic meter, port scanner.... I also tried erasing to no avail. I have IPv6 enabled for this test so I am not sure why it is saying false.

client
dev tun
proto udp
remote all.ddnskey.com 12973
nobind
ca ca.crt
cert client.crt
key client.key
cipher AES-128-CBC
comp-lzo
verb 5
sndbuf 393216
rcvbuf 393216

[Nov 15, 2025, 15:51:13] OpenVPN core 3.11.3 win x86_64 64-bit OVPN-DCO built on Sep 16 2025 15:58:53
⏎[Nov 15, 2025, 15:51:13] Frame=512/2112/512 mssfix-ctrl=1250
⏎[Nov 15, 2025, 15:51:13] EVENT: RESOLVE ⏎[Nov 15, 2025, 15:51:14] Contacting x.x.x.x:12973 via UDP
⏎[Nov 15, 2025, 15:51:14] EVENT: WAIT ⏎[Nov 15, 2025, 15:51:14] WinCommandAgent: transmitting bypass route to x.x.x.x
{
"host" : "x.x.x.x",
"ipv6" : false
}

loop

⏎[Nov 15, 2025, 15:51:53] Connecting to [all.ddnskey.com]:12973 (x.x.x.x) via UDP
⏎[Nov 15, 2025, 15:52:03] Server poll timeout, trying next remote entry...
⏎[Nov 15, 2025, 15:52:03] EVENT: RECONNECTING ⏎[Nov 15, 2025, 15:52:03] EVENT: RESOLVE ⏎[Nov 15, 2025, 15:52:03] Contacting x.x.x.x:12973 via UDP
⏎[Nov 15, 2025, 15:52:03] EVENT: WAIT ⏎[Nov 15, 2025, 15:52:03] WinCommandAgent: transmitting bypass route to x.x.x.x
{
"host" : "x.x.x.x",
"ipv6" : false
}

⏎[Nov 15, 2025, 15:52:04] Connecting to [all.ddnskey.com]:12973 (x.x.x.x) via UDP
⏎[Nov 15, 2025, 15:52:13] EVENT: CONNECTION_TIMEOUT BYTES_OUT : 840
PACKETS_OUT : 60
CONNECTION_TIMEOUT : 1
N_RECONNECT : 5
⏎[Nov 15, 2025, 15:52:13] EVENT: DISCONNECTED ⏎

Nmap scan report for c-x-x-x-x.hsd1.or.comcast.net (x.x.x.x)
Host is up.

PORT STATE SERVICE
12973/udp open|filtered unknown
12974/udp open|filtered unknown

Nmap done: 1 IP address (1 host up) scanned in 5.62 seconds

5_D · Answer

The smartphone config file already had verb 5. I tried with windows via Verizon hotspot. I had to edit the config for tun and remove lines for it to work. I have tried rebooting after changing: IPv6, UPnP, port #, traffic meter, port scanner.... I also tried erasing to no avail. I have IPv6 enabled for this test so I am not sure why it is saying false.

client
dev tun
proto udp
remote all.ddnskey.com 12973
nobind
ca ca.crt
cert client.crt
key client.key
cipher AES-128-CBC
comp-lzo
verb 5
sndbuf 393216
rcvbuf 393216

Forum Discussion

VPN Ports Closed -> VPN Timeout

6 Replies