If you're getting a Docker error like:
(HTTP code 500) server error - ports are not available: exposing port TCP 0.0.0.0:8182 -> 127.0.0.1:0: listen tcp 0.0.0.0:8182: bind: An attempt was made to access a socket in a way forbidden by its access permissions.
But nothing is using the port, it’s likely because Windows has excluded the port dynamically, especially after Docker was previously using it.
 |
| (HTTP code 500) server error - ports are not available |
1. Verify Nothing Is Listening on the Port
netstat -aon | findstr :8181
If you see no output, the port is not in use by any application.
2. Check Excluded Port Ranges:
netsh interface ipv4 show excludedportrange protocol=tcp
Protocol tcp Port Exclusion Ranges
Start Port End Port
---------- --------
6575 6674
7162 7261
7262 7361
7362 7461
7462 7561
7562 7661
7681 7780
7781 7880
7881 7980
7981 8080
8081 8180
8181 8280
8281 8380
8381 8480
8481 8580
30604 30703
49690 49789
49790 49889
49890 49989
50000 50059 *
50160 50259
50360 50459
50460 50559
50660 50759
50760 50859
50860 50959
51064 51163
51243 51342
51344 51443
You’ll notice 8182 falls within the 8181–8280 range - without a * at the end, meaning it's a dynamically excluded port.
You cannot remove dynamic exclusions manually.
3. Restart winnat Service to Clear Dynamic Exclusions:
This step clears dynamic port reservations created by services like Docker:
net stop winnat net start winnat
* Run the above in Administrator Command Prompt
4. Recheck Excluded Ports:
netsh int ipv4 show excludedportrange protocol=tcp
Protocol tcp Port Exclusion Ranges
Start Port End Port
---------- --------
50000 50059 *
* - Administered port exclusions.
If 8182 is no longer in the list, you're good to go.
