I installed Postgres on my Windows 10 21H1 machine and was not able to start the database server - it insisted that port 5432 was in use.
Event Viewer showed the following:
2021-08-14 13:03:04.273 AEST [19608] FATAL: could not create any TCP/IP sockets
I got suspicious when running the server manually on different ports:
PS C:\Users\Adam> & "C:\Program Files\PostgreSQL\12\bin\postgres.exe" -D "B:\db" -p5430
2021-08-14 13:12:44.164 AEST [19176] LOG: starting PostgreSQL 12.7, compiled by Visual C++ build 1914, 64-bit
2021-08-14 13:12:44.165 AEST [19176] LOG: could not bind IPv4 address "127.0.0.1": Permission denied
2021-08-14 13:12:44.165 AEST [19176] HINT: Is another postmaster already running on port 5430? If not, wait a few secon2021-08-14 13:12:44.165 AEST [19176] WARNING: could not create listen socket for "127.0.0.1"
2021-08-14 13:12:44.165 AEST [19176] FATAL: could not create any TCP/IP sockets
2021-08-14 13:12:44.166 AEST [19176] LOG: database system is shut down
PS C:\Users\Adam> & "C:\Program Files\PostgreSQL\12\bin\postgres.exe" -D "B:\db" -p5400
2021-08-14 13:14:11.689 AEST [19560] LOG: starting PostgreSQL 12.7, compiled by Visual C++ build 1914, 64-bit
2021-08-14 13:14:11.690 AEST [19560] LOG: could not bind IPv4 address "127.0.0.1": Permission denied
2021-08-14 13:14:11.690 AEST [19560] HINT: Is another postmaster already running on port 5400? If not, wait a few seconds and retry.
2021-08-14 13:14:11.690 AEST [19560] WARNING: could not create listen socket for "127.0.0.1"
PS C:\Users\Adam> & "C:\Program Files\PostgreSQL\12\bin\postgres.exe" -D "B:\db" -p5300
2021-08-14 13:14:15.096 AEST [19660] LOG: redirecting log output to logging collector process
(I’d already changed postgresql.conf to have 127.0.0.1 as the host just in case * or localhost was causing issues)
So 5432, 5430, 5400 are out but 5300 works? Right, Windows is lying to me again.
Infuriatingly, all the posts about this told me to run netstat or TCPView, which is great except the port wasn’t in use. Eventually I was led to the following command:
netsh int ipv4 show excludedportrange protocol=tcp
Protocol tcp Port Exclusion Ranges
Start Port End Port
---------- --------
1063 1162
1163 1262
1263 1362
1363 1462
1463 1562
1678 1777
1778 1877
1878 1977
1978 2077
2207 2306
2400 2499
2500 2599
2600 2699
2906 3005
3006 3105
3106 3205
3206 3305
3390 3489
3490 3589
3590 3689
4001 4100
4101 4200
4201 4300
4301 4400
4401 4500
4501 4600
4601 4700
4912 5011
5041 5140
5141 5240
5357 5357
5358 5457
50000 50059 *
* - Administered port exclusions.
So there’s an “Administered port exclusion” for TCP ports 5358-5457, which happens to include Postgres’ default 5432.
Of course, Googling doesn’t bring you to a Microsoft explanation straight away, only a StackOverflow answer. If you really want to use 5432 you’ll need to disable Hyper-V, change the port exclusion, then re-enable Hyper-V.
These links will help:
https://stackoverflow.com/a/65234135/229631
https://pomeroy.me/2020/09/solved-windows-10-forbidden-port-bind/
For my use, changing Postgres’ listen port to something else was fine (i.e. port = 55432 in postgresql.conf)