[BDS-3989] Default server port is used even if another port is defined

Summary
When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Note that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
The additional ports should be from a higher, unused range

How this impacts server owners:
If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19134 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

Linked Issues

is duplicated by3

BDS-4552Server always listens on port 19132 even if another port is setDuplicate

BDS-4620Server listens on more than 2 ports when server.properties is configured to use non-default ports.Duplicate

BDS-9819When using other port numbers than default, default ports are still locked/in useDuplicate

relates to1

BDS-1094Additional IPv4 and IPv6 port opening upon starting serverFixed

Comments15

AsherMaximum 2020-01-19, 09:02:35 AM

I am having this issue in 1.14 as well. If I start the server on 19132 first, starting the one on 19134 doesn't try to use 19132, however, the server is not able to be connected to.

IonicEcko 2020-05-27, 11:49:43 AM

Original Description by Jahus:
From server.properties:

server-port=19131
server-portv6=19134

When server is ran:

… }}{{INFO] IPv4 supported, port: 19131
… }}{{INFO] IPv6 supported, port: 19134
… }}{{INFO] IPv4 supported, port: 19132
… }}{{INFO] IPv6 supported, port: 19133
… }}{{INFO] Server started.

As you can see, the server ran on defined ports, but also on default ones.

It looks like the server always runs 2 other ports after running on the ones defined in server.properties.

In instance, if you set default ports in server.properties, the server adds two random ports.

Example:

… }}{{INFO] IPv4 supported, port: 19131
… }}{{INFO] IPv6 supported, port: 19134
… }}{{INFO] IPv4 supported, port: 42484
… }}{{INFO] IPv6 supported, port: 54985
… }}{{INFO] Server started.

I don't see why it should do such a thing. Especially that if the ports are random, we can't create a proper firewall rule for them.

Finally, I want to point out that this behavior is new and wasn't present in 1.11.2.1. Here is a typical output from the latter:

… }}{{INFO] IPv4 supported, port: 19131
… }}{{INFO] IPv6 supported, port: 19134
… }}{{INFO] Server started.

This issue is preventing me from launching 2 servers as services; one on default ports (needed) and another on other ports because the one that doesn't use default port may occupy default ports if ran first. This would make the other server unable to run because the ports are already in use.

/dev/urandom 2020-06-24, 11:55:11 AM

I can confirm the issue in 1.16 as well

Cr@shedC0w 2020-07-13, 10:56:37 PM

This is confirmed in 1.16.1.

Kai 2020-12-15, 11:59:00 PM

This issue still persists in 1.16.201 as of December 15th, 2020 and has also been in 1.16.100 and 1.16.200 (if affected versions shall be updated)

@[Mod] OcelotOnesie, is there any chance for this Bug to be fixed any time soon? As a Linux bedrock server user with multiple different worlds for different groups it's a real pain in the backside to have only one server running at any given time.

Thank you for updating us!

Kai

Omkhar 2020-12-19, 05:29:43 PM

I can confirm this issue on multiple versions of the Bedrock Linux server I’ve tried through 2020. I have resorted to rather hacky work arounds. The network code for the Linux port appears quite defective. Why isn’t this being prioritized or addressed?

Pieter Jan Prijs 2021-01-28, 12:38:47 PM

Can confirm this also happening with windows version 1.16.201.2 on Windows 10.

It is a real PITA since if my default server crashes, and my secondary server restarts, it takes up the default port.

Took me a while the first time to figure out why the default port was already in use...

Kristian Domke 2021-01-30, 02:15:19 PM

As it really is a problem to navigate around, it should be fixed at last.

Kai 2021-03-20, 07:07:11 PM

I bet you know what I was gonna comment, still affects 1.16.210.06.

Thomas Walker 2021-04-25, 06:37:59 AM

I recently came across this bug and am similarly frustrated with how long this has been open. It looks like Mojang is opening those for "auto-discovery" to work but if you don't care about that, this is seriously annoying.

For those using Linux, I do have a quick, exceedingly ugly hack to work around this though. This is, admittedly, hideous. But it works!

tldr, this hooks calls to glibc bind() and, if the requested port is 19132 or 19133, redirects it into the ephemeral range (typically 32768-61000) where they won't get in the way of anything. Yes, it would be much cleaner to simply not open them at all, but this is simply transparent to bedrock_server (it just thinks it opened the ports and nobody is connecting to them).

Working happily with multiple bedrock_server instances on one system (obviously no auto-discovery) and using BedrockConnect (which uses the default ports).

/*
 * An incredibly ugly hack to hook bedrock_server's
 * superfluous bind to the default ports (19132 and 19133)
 * and redirect them out of the way into the ephemeral range
 *
 * Instructions:
 * Save this file as bindhook.c in the same dir as bedrock_server
 * compile with `gcc -o libhook.so -shared -fPIC -ldl bindhook.c`
 * run with `LD_PRELOAD=./libhook.so ./bedrock_server`
 */

#define _GNU_SOURCE
#include <dlfcn.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <stddef.h>

int bind (int fd, const struct sockaddr *sk, socklen_t sl) {
    static int (*real_bind)(int, const struct sockaddr *, socklen_t) = NULL;
    static struct sockaddr_in *sk_in;
    uint16_t port;

    if (!real_bind)
        real_bind = dlsym(RTLD_NEXT, "bind");
    // AF_INET or AF_INET6, sin_port is in the same place
    sk_in = (struct sockaddr_in *) sk;
    port = ntohs(sk_in->sin_port);
    if ((port == 19132) || (port == 19133))
        sk_in->sin_port = htons(0);
    return real_bind(fd, sk, sl);
}

This should theoretically be possible on Windows as well using DLL injection and API hooks, but it is much more involved than a simple call to dlsym() and I haven't really worked on Windows for 20+ years at this point.

GameParrot 2022-04-07, 10:48:57 PM

edited 2022-04-07, 10:49:07 PM

This is also annoying because it means that friends can't join a single-player world even if the server is on a different port.

Kai 2022-05-13, 12:17:28 AM

As @Thomas Walker said, my guess is that these ports are used for auto-discovery.

For security reasons I sincerely think, that server admins of small / family- / church- / school-servers should be able to deactivate the auto-discovery for publicly accessible IPs through server.properties.

I dunno, @Mojang, if you really think auto-discovery should stay non-deactivatable and thus us being unable to run multiple worlds on one machine, could we please get a "won't fix" on this issue so that people stop reporting and checkin on this issue every so often?

Thx!

Kai 2023-06-17, 10:30:51 PM

edited 2023-06-17, 10:31:19 PM

@Mods, I guess this issue can be closed as there is now the option to turn the default port discovery on and off since 1.19.50 (See ~~BDS-1094~~)

Jahus 2023-06-18, 06:17:53 PM

@Kai, do you confirm that the port is not used if the new option is toggled?

Smell of Curry 2023-12-20, 03:05:25 PM

edited 2023-12-20, 03:13:38 PM

This issue is still a problem and causes severe issues when running multiple servers on the same machine. If BDS finds the default port open it will automatically bind to that port, however, when people try to connect to that port, it will show that the server is popular which makes no sense.

This is a serious issue and needs to be fixed, its a shame this has been open for as long as it has.

EDIT:

Set `enable-lan-visibility=false` in `server.properties`.

History22

Jahus 2019-08-05, 07:35:08 PM

Changed summary:
Default server port number is used even if another port is defined

[Mod] OcelotOnesie 2020-04-08, 07:42:22 PM

Key

Platform

project

Added affects versions: 1.14.32.1

Removed affects versions: 1.14.32.1

IonicEcko 2020-05-27, 11:48:38 AM

Changed description:

From server.properties:

server-port=19131
0server-portv6=19134

When server is ran:

… }}{{INFO] IPv4 supported, port: 19131
0… }}{{INFO] IPv6 supported, port: 19134
0… }}{{INFO] IPv4 supported, port: 19132
0… }}{{INFO] IPv6 supported, port: 19133
0… }}{{INFO] Server started.

As you can see, the server ran on defined ports, but also on default ones.

It looks like the server always runs 2 other ports after running on the ones defined in server.properties.

In instance, if you set default ports in server.properties, the server adds two random ports.

Example:

… }}{{INFO] IPv4 supported, port: 19131
0… }}{{INFO] IPv6 supported, port: 19134
0… }}{{INFO] IPv4 supported, port: 42484
0… }}{{INFO] IPv6 supported, port: 54985
0… }}{{INFO] Server started.

I don't see why it should do such a thing. Especially that if the ports are random, we can't create a proper firewall rule for them.

Finally, I want to point out that this behavior is new and wasn't present in 1.11.2.1. Here is a typical output from the latter:

… }}{{INFO] IPv4 supported, port: 19131
0… }}{{INFO] IPv6 supported, port: 19134
0… }}{{INFO] Server started.

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server

Not that the additional open ports are 19132 and 19133 rather than from the usual random range.

What I expected to happen:
0The additional ports should be from a higher, unused range, the server adds two random ports.

How this impacts server owners:
0If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19132 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

0000

IonicEcko 2020-05-27, 11:50:00 AM

Changed description:

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

How this impacts server owners:
0If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19132 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

IonicEcko 2020-05-27, 11:50:10 AM

Confirmation Status: Unconfirmed → Confirmed

IonicEcko 2020-05-27, 11:51:47 AM

Added is duplicated by link:
BDS-4552Server always listens on port 19132 even if another port is setDuplicate

[Bot] Arisa 2020-05-27, 11:52:00 AM

Added affects versions: 1.14.60

IonicEcko 2020-05-27, 11:52:13 AM

Changed description:

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports (~~BDS-1094~~) rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

IonicEcko 2020-05-27, 11:52:40 AM

Changed description:

Summary
0When non-standard ports are available, BDS will use them as the "additional" automatic ports (~~BDS-1094~~) rather than in the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

[Mojang] Mega_Spud (Jay Wells) 2020-05-27, 11:54:33 AM

Added relates to link:
BDS-1094Additional IPv4 and IPv6 port opening upon starting serverFixed

[Mojang] Mega_Spud (Jay Wells) 2020-05-27, 11:55:05 AM

Changed description:

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

IonicEcko 2020-05-27, 12:11:14 PM

Changed description:

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

How this impacts server owners:
0If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19134 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

Jahus 2020-05-27, 04:20:58 PM

Changed description:

Summary
0When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Not that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0The additional ports should be from a higher, unused range

Original description moved to comments for clarity

Summary
0 When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Note that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0 The additional ports should be from a higher, unused range

How this impacts server owners:
0 If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19134 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity for clarity

IonicEcko 2020-05-27, 05:21:21 PM

Changed description:

Summary
0 When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Note that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0 The additional ports should be from a higher, unused range

How this impacts server owners:
0 If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19134 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

Summary
0 When non-standard ports are available, BDS will use the standard ports as the "additional" automatic ports (~~BDS-1094~~) rather than ones from the normal random range.

Steps to Reproduce:

Modify server-port and server-portv6 to 19131 and 19134 respectively
Start server
Note that the additional open ports are 19132 and 19133 rather than from the usual random range

What I expected to happen:
0 The additional ports should be from a higher, unused range

How this impacts server owners:
0 If you have 2 servers, one that is configured to run on 19132 and 19133 (BDS A) and another to run on 19134 and 19135 (BDS B). If when starting the server, BDS B starts before BDS A it will consume 19132 and 33 as its random ports preventing BDS A from starting (due to ports being in use)

Original description moved to comments for clarity

IonicEcko 2020-06-21, 05:37:05 AM

Added is duplicated by link:
BDS-4620Server listens on more than 2 ports when server.properties is configured to use non-default ports.Duplicate

IonicEcko 2020-06-24, 12:16:59 PM

Added affects versions: 1.16.0

IonicEcko 2020-10-07, 04:00:36 AM

Added affects versions: 1.16.40

IonicEcko 2020-11-18, 08:01:40 AM

Added is duplicated by link:
BDS-9819When using other port numbers than default, default ports are still locked/in useDuplicate

[Mojang] Mega_Spud (Jay Wells) 2023-07-07, 03:19:13 PM

Resolution: Unresolved → Fixed

Added affects versions: 1.20.1 Hotfix