`qbittorrent-nox` is installed on `OpenBSD`. I can access its WebUI from `localhost`, but can't from another machine - connection refused. From another machine I can access pages served by `httpd` and `python3 -m http.server 8000` and `python3 -m http.server 8080` (the port used by `qbittorrent-nox`). I can remotely access `qbittorrent-nox` that is installed on `Linux` in the same network setup. I have 2 `OpenBSD` machines (a headless NAS and a laptop), both have `qbittorrent-nox` unreachable. Any hints? Thank you ### Update (the accepted answers): from [post #9](https://www.unitedbsd.com/d/634-qbittorrent-nox-connection-refused/9) by @"rvp"#168, here edited by me: > @"rvp"#p9958 `OpenBSD` has a peculiarity which is explained in [`man 4 ip6`](http://man.openbsd.org/amd64/ip6#IPV6_V6ONLY). > > When you open a listen-socket, you can choose to set an option called `IPV6_V6ONLY`. With this set to `0`, an `IPv6` server socket will listen on _both_ `IPv6` and `IPv4` addresses. > Most programs set this to `0` so that they need not open 2 server sockets for the same port. > > However, on `OpenBSD`, as [the man-page](http://man.openbsd.org/amd64/ip6#IPV6_V6ONLY) explains: >``` > IPV6_V6ONLY int * > Get or set whether only IPv6 connections can be made to this socket. For wildcard > sockets, this can restrict connections to IPv6 only. With OpenBSD IPv6 sockets are > always IPv6-only, so the socket option is read-only (not modifiable). > ``` > So there you have it: I think (I haven't read the code, mind) that `qbittorrent` is setting that option to `0` when the `WebUI\Address=` field is `*` (listen on all), expecting the server will listen on both `IPv6` & `IPv4` addresses, but, this doesn't work on `OpenBSD`. from [post #11](https://www.unitedbsd.com/d/634-qbittorrent-nox-connection-refused/11) by @"rvp"#168, here edited by me: > @"rvp"#p9962 one standard workaround for this is to add an `IPv6` address (and an `AAAA` record in your DNS config) to the host running `qbittorrent`. This way, even if `qbittorrent` only listens on an `IPv6` address, as long as clients use hostnames instead of IP addresses (and support `IPv6`) the connection will succeed. #### What I have done so that it works for me, OP: I have put `localhost` into `~/.config/qBittorrent/qBittorrent.conf`: ``` WebUI\Address=localhost ``` and I get in `~/.local/share/qBittorrent/logs/qbittorrent.log`: ``` (N) 2022-01-04T22:26:30 - Web UI: Now listening on IP: localhost, port: 8080 ``` and now I can log into Web UI both from localhost and remotely. This also works: from [post #5](https://www.unitedbsd.com/d/634-qbittorrent-nox-connection-refused/5): > @"uxer"#p9951 I put my LAN into `~/.config/qBittorrent/qBittorrent.conf`: > ``` > WebUI\Address=192.168.88.* > ``` > and I got in `~/.local/share/qBittorrent/logs/qbittorrent.log`: > ``` > (N) 2022-01-01T00:29:37 - Web UI: Now listening on IP: 192.168.88.*, port: 8080 > ``` > and I could log into Web UI both from localhost and remotely. _(However, I am not actually sure that `WebUI\Address=192.168.88.*` opens access to `192.168.88.*`. I tried being more specific feeding `192.168.88.10-192.168.88.254` range, and tested it by specifying a narrower `192.168.88.10-192.168.88.251` range, leaving my `252` machine out. I did 3 tries: `192.168.88.10-251`; `192.168.88.10-192.168.88.251` and `"192.168.88.10/31,192.168.88.12/30,192.168.88.16/28,192.168.88.32/27,192.168.88.64/26,192.168.88.128/26,192.168.88.192/27,192.168.88.224/28,192.168.88.240/29,192.168.88.248/30"` ([converter](https://www.meridianoutpost.com/resources/etools/network/convert-ip-to-CIDR.php)). Nope, I still could connect from `252`. Dunno)_

qbittorrent-nox connection refused

uxer

qbittorrent-nox is installed on OpenBSD. I can access its WebUI from localhost, but can't from another machine - connection refused.

From another machine I can access pages served by httpd and python3 -m http.server 8000 and python3 -m http.server 8080 (the port used by qbittorrent-nox).
I can remotely access qbittorrent-nox that is installed on Linux in the same network setup.

I have 2 OpenBSD machines (a headless NAS and a laptop), both have qbittorrent-nox unreachable.

Any hints? Thank you

Update (the accepted answers):

from post #9 by @rvp, here edited by me:

rvp OpenBSD has a peculiarity which is explained in man 4 ip6.

When you open a listen-socket, you can choose to set an option called IPV6_V6ONLY. With this set to 0, an IPv6 server socket will listen on both IPv6 and IPv4 addresses.
Most programs set this to 0 so that they need not open 2 server sockets for the same port.

However, on OpenBSD, as the man-page explains:
IPV6_V6ONLY int *
      Get or set whether only IPv6 connections can be made to this socket. For wildcard
      sockets, this can restrict connections to IPv6 only. With OpenBSD IPv6 sockets are
      always IPv6-only, so the socket option is read-only (not modifiable).
So there you have it: I think (I haven't read the code, mind) that qbittorrent is setting that option to 0 when the WebUI\Address= field is * (listen on all), expecting the server will listen on both IPv6 & IPv4 addresses, but, this doesn't work on OpenBSD.

from post #11 by @rvp, here edited by me:

rvp one standard workaround for this is to add an IPv6 address (and an AAAA record in your DNS config) to the host running qbittorrent. This way, even if qbittorrent only listens on an IPv6 address, as long as clients use hostnames instead of IP addresses (and support IPv6) the connection will succeed.

What I have done so that it works for me, OP:

I have put localhost into ~/.config/qBittorrent/qBittorrent.conf:

WebUI\Address=localhost

and I get in ~/.local/share/qBittorrent/logs/qbittorrent.log:

(N) 2022-01-04T22:26:30 - Web UI: Now listening on IP: localhost, port: 8080

and now I can log into Web UI both from localhost and remotely.

This also works: from post #5:

uxer I put my LAN into ~/.config/qBittorrent/qBittorrent.conf:

WebUI\Address=192.168.88.*

and I got in ~/.local/share/qBittorrent/logs/qbittorrent.log:

(N) 2022-01-01T00:29:37 - Web UI: Now listening on IP: 192.168.88.*, port: 8080

and I could log into Web UI both from localhost and remotely.

(However, I am not actually sure that WebUI\Address=192.168.88.* opens access to 192.168.88.*. I tried being more specific feeding 192.168.88.10-192.168.88.254 range, and tested it by specifying a narrower 192.168.88.10-192.168.88.251 range, leaving my 252 machine out. I did 3 tries: 192.168.88.10-251; 192.168.88.10-192.168.88.251 and "192.168.88.10/31,192.168.88.12/30,192.168.88.16/28,192.168.88.32/27,192.168.88.64/26,192.168.88.128/26,192.168.88.192/27,192.168.88.224/28,192.168.88.240/29,192.168.88.248/30" (converter). Nope, I still could connect from 252. Dunno)

rvp

uxer Any hints?

Is qbittorrent-nox listening on addresses other than localhost? What does sockstat -l show?

uxer

Hey, rvp! Glad you replied.

sockstat seems to not be present on OpenBSD (tried as a regular user; via su; and logged in as root via tty), and not available from packages: pkg_info -Q sockstat returns nothing.

But you have given me a push in the right direction.

from nmap localhost:

PORT   STATE SERVICE
22/tcp open  ssh
25/tcp open  smtp
80/tcp open  http

from nmap -6 localhost:

PORT     STATE SERVICE
22/tcp   open  ssh
25/tcp   open  smtp
80/tcp   open  http
8080/tcp open  http-proxy

from netstat:

Active Internet connections
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  localhost.35164        localhost.8080         ESTABLISHED
tcp6         0      0  localhost.34084        localhost.8080         ESTABLISHED
tcp6         0      0  localhost.8080         localhost.35164        ESTABLISHED
tcp6         0      0  localhost.8080         localhost.34084        ESTABLISHED

So, qbittorrent-nox is running on IPv6. It probably shouldn't be v6-only?

from ~/.local/share/qBittorrent/logs/qbittorrent.log:

(N) 2021-12-31T19:17:29 - Web UI: Now listening on IP: *, port: 8080

The * asterisk probably means both v4 and v6 or at least not v6-only?

from grep -i webui ~/.config/qBittorrent/qBittorrent.conf:

WebUI\Address=*
WebUI\AlternativeUIEnabled=false
WebUI\AuthSubnetWhitelist=@Invalid()
WebUI\AuthSubnetWhitelistEnabled=false
WebUI\BanDuration=3600
WebUI\CSRFProtection=true
WebUI\ClickjackingProtection=true
WebUI\CustomHTTPHeaders=
WebUI\CustomHTTPHeadersEnabled=false
WebUI\HTTPS\CertificatePath=
WebUI\HTTPS\Enabled=false
WebUI\HTTPS\KeyPath=
WebUI\HostHeaderValidation=true
WebUI\LocalHostAuth=true
WebUI\MaxAuthenticationFailCount=5
WebUI\Port=8080
WebUI\RootFolder=
WebUI\SecureCookie=true
WebUI\ServerDomains=*
WebUI\SessionTimeout=3600
WebUI\UseUPnP=true
WebUI\Username=admin

Now, what could you suggest me to do?
Force qbittorrent-nox to use v4? But it should already use v4, shouldn't it? If force, how? I feel lost.

rvp

uxer Can you change the WebUI\Address line to this and restart qbittorrent-nox?

$ fgrep 'WebUI\Address' ~/.config/qBittorrent/qBittorrent.conf 
WebUI\Address="*,*"
$

You can also make the change (*,*) in the WebUI: Tools > Options > WebUI > IP Address

uxer

rvp

It seems to work.

I had put my machine's LAN IP into ~/.config/qBittorrent/qBittorrent.conf:

WebUI\Address=192.168.88.245

and I got in ~/.local/share/qBittorrent/logs/qbittorrent.log:

(N) 2021-12-31T23:40:29 - Web UI: Now listening on IP: 192.168.88.245, port: 8080

and I could log into Web UI remotely.

But, having specified the IP, I couldn't access Web UI from localhost, even though the qbittorrent-nox kept printing:

To control qBittorrent, access the Web UI at http://localhost:8080

I put my LAN into ~/.config/qBittorrent/qBittorrent.conf:

WebUI\Address=192.168.88.*

and I got in ~/.local/share/qBittorrent/logs/qbittorrent.log:

(N) 2022-01-01T00:29:37 - Web UI: Now listening on IP: 192.168.88.*, port: 8080

and I could log into Web UI both from localhost and remotely.

But again, I would expect the asterisk * to stand for any. Am I wrong?
Should WebUI\Address=* work fine?

rvp Do you have a firewall blocking things?

No, firewall doesn't block this thing, as far as I understand vanilla OpenBSD's /etc/pf.conf:

#       $OpenBSD: pf.conf,v 1.55 2017/12/03 20:40:04 sthen Exp $
#
# See pf.conf(5) and /etc/examples/pf.conf

set skip on lo

block return    # block stateless traffic
pass            # establish keep-state

# By default, do not permit remote connections to X11
block return in on ! lo0 proto tcp to port 6000:6010

# Port build user does not need network
block return out log proto {tcp udp} user _pbuild

And MikroTik router vanilla rules:
/ip firewall filter> print:

Flags: X - disabled, I - invalid, D - dynamic
 0  D ;;; special dummy rule to show fasttrack counters
      chain=forward action=passthrough

 1    ;;; defconf: accept established,related,untracked
      chain=input action=accept connection-state=established,related,untracked

 2    ;;; defconf: drop invalid
      chain=input action=drop connection-state=invalid

 3    ;;; defconf: accept ICMP
      chain=input action=accept protocol=icmp

 4    ;;; defconf: accept to local loopback (for CAPsMAN)
      chain=input action=accept dst-address=127.0.0.1

 5    ;;; defconf: drop all not coming from LAN
      chain=input action=drop in-interface-list=!LAN

 6    ;;; defconf: accept in ipsec policy
      chain=forward action=accept ipsec-policy=in,ipsec

 7    ;;; defconf: accept out ipsec policy
      chain=forward action=accept ipsec-policy=out,ipsec

 8    ;;; defconf: fasttrack
      chain=forward action=fasttrack-connection connection-state=established,related

 9    ;;; defconf: accept established,related, untracked
      chain=forward action=accept connection-state=established,related,untracked

10    ;;; defconf: drop invalid
      chain=forward action=drop connection-state=invalid

11    ;;; defconf: drop all from WAN not DSTNATed
      chain=forward action=drop connection-state=new connection-nat-state=!dstnat in-interface-list=WAN

rvp What's your netstat show?

without qbittorrent-nox running:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  ::1.25                 *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN

with WebUI\Address=* in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible from localhost; inaccessible remotely:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.8080                 *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  ::1.25                 *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN
tcp6         0      0  *.80                   *.*                    LISTEN

with WebUI\Address=127.0.0.1 in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible from localhost; inaccessible remotely:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  127.0.0.1.8080         *.*                    LISTEN
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN
tcp6         0      0  ::1.25                 *.*                    LISTEN

with WebUI\Address=localhost in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible both from localhost and remotely:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
tcp          0      0  *.8080                 *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN
tcp6         0      0  ::1.25

with WebUI\Address=192.168.88.245 (the host's address) in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible remotely; inaccessible from localhost despite qbittorrent-nox's message access the Web UI at http://localhost:8080:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
tcp          0      0  192.168.88.245.8080    *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  *.80                   *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  ::1.25                 *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN

with WebUI\Address=192.168.88.* in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible both from localhost and remotely:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  *.8080                 *.*                    LISTEN
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  ::1.25                 *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN

rvp WebUI\Address=","

[offtopic] @unitedbsd.com - the asterisks got swallowed by your parsers. The text is > @"rvp"#p9949 WebUI\Address="*,*" [/offtopic]

with WebUI\Address="*,*" in ~/.config/qBittorrent/qBittorrent.conf and qbittorrent-nox running,
Web UI accessible both from localhost and remotely:
netstat -ln -p tcp:

Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp          0      0  192.168.88.245.61079   *.*                    LISTEN
tcp          0      0  *.80                   *.*                    LISTEN
tcp          0      0  127.0.0.1.25           *.*                    LISTEN
tcp          0      0  *.22                   *.*                    LISTEN
tcp          0      0  *.8080                 *.*                    LISTEN
Active Internet connections (only servers)
Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.80                   *.*                    LISTEN
tcp6         0      0  *.22                   *.*                    LISTEN
tcp6         0      0  ::1.25                 *.*                    LISTEN
tcp6         0      0  fe80::1%lo0.25         *.*                    LISTEN

rvp What does *,* mean?

Could someone explain me the abovementioned ¿peculiarities?, so to say, or should I submit an issue?
Is it an issue for the qbittorrent's tracker of for qbittorrent's port to OpenBSD?

rvp

uxer What does *,* mean?

The first * is to listen on any IPv6 address; the second for any IPv4 address.

uxer

rvp

rvp The first * is to listen on any IPv6 address; the second for any IPv4 address.

Then I should see in netstat -ln -p tcp:

Proto   Recv-Q Send-Q  Local Address          Foreign Address        TCP-State
tcp6         0      0  *.8080                 *.*                    LISTEN

But I don't.

So, do you find here some strangeness worth of opening an issue, or is it me who doesn't RTFM enough?

rvp

uxer Then I should see in netstat -ln -p tcp:

You're right. I've no clue what's going on. Turns out you can put in any junk and it'll bind to any IPv4 address (only). Leaving it blank, or just a * binds only to any IPv6 address.

RTFM first, then open an issue. (always the courteous policy, no?)

rvp

rvp I've no clue what's going on.

Alrighty---writing a test program or two (and a little bit of RTFM) told me what's going on.

OpenBSD has a peculiarity which is explained in ip6.

When you open a listen-socket, you can choose to set an option called IPV6_V6ONLY. With this set to 0, an IPv6 server socket will listen on both IPv6 and IPv4 addresses. (The OS default can be seen with: sysctl net.inet6.ip6.v6only)
Most programs set this to 0 so that they need not open 2 server sockets for the same port.

However, on OpenBSD, as the man-page explains:

IPV6_V6ONLY int *
      Get or set whether only IPv6 connections can be made to this socket. For wildcard
      sockets, this can restrict connections to IPv6 only. With OpenBSD IPv6 sockets are
      always IPv6-only, so the socket option is read-only (not modifiable).

So there you have it: I think (I haven't read the code, mind) that qbittorrent is setting that option to 0 when the IP address field is *, expecting the server will listen on both IPv6 & IPv4 addresses, but, this doesn't work on OpenBSD.

So, we've RTFM, and now you can file a PR. 😁

uxer

rvp RTFM first, then open an issue. (always the courteous policy, no?)

Witty.

IPV6_V6ONLY int *
      Get or set whether only IPv6 connections can be made to this socket. For wildcard
      sockets, this can restrict connections to IPv6 only. With OpenBSD IPv6 sockets are
      always IPv6-only, so the socket option is read-only (not modifiable).

Get or set

are always IPv6-only, so the socket option is read-only (not modifiable).

Is that a typo in that section of manpage, or need I first to learn something special to the manpages? If the option is read-only and not modifiable, then how does one set it?

rvp The OS default can be seen with: sysctl net.inet6.ip6.v6only

It replies: sysctl: fourth level name v6only in net.inet6.ip6.v6only is invalid
And https://man.openbsd.org/sysctl.2 says nothing on v6only

From https://man.openbsd.org/amd64/ip6 :

These options and other control requests are accessed with the getsockopt(2) and setsockopt(2) system calls at level IPPROTO_IPV6 and by using ancillary data in recvmsg(2) and sendmsg(2)

I mean no user-accessible utility is mentioned to check IPV6_V6ONLY.

rvp So, we've RTFM, and now you can file a PR. 😁

PR as in Problem Report - lovely.
PR as in Pull Request - well, maybe in several years from now, since for a PR I'll need to learn C++ & Qt first, even if. Sorry for not being on par with challenges.

rvp

uxer If the option is read-only and not modifiable, then how does one set it?

It's read-only on OpenBSD; on the other BSDs and Linux you can set it to 0.

uxer It replies: sysctl: fourth level name v6only in net.inet6.ip6.v6only is invalid

Might not exist on OpenBSD, since IPv6 sockets there are always IPv6-only (as the man-page explains). Try this check:

sysctl -a | fgrep 6only

Edit: BTW, one standard workaround for this is to add an IPv6 address (and an AAAA record in your DNS config.) to the host running qbittorrent. This way, even if qbittorrent only listens on an IPv6 address, as long as clients use hostnames instead of IP addresses (and support IPv6) the connection will succeed.

uxer

rvp uxer If the option is read-only and not modifiable, then how does one set it?
rvp It's read-only on OpenBSD
rvp IPv6 sockets there are always IPv6-only (as the man-page explains)

I mean in the OpenBSD man 4 ip6, IPV6_V6ONLY section there is the word set in the phrase Get or set. This set contradicts read-only (not modifiable) found at the same section.

rvp sysctl -a | fgrep 6only

Nothing, and # sysctl | egrep -i '^net.+6.*o' false positives only.

rvp BTW, one standard workaround for this is to add an IPv6 address (and an AAAA record in your DNS config.) to the host running qbittorrent. This way, even if qbittorrent only listens on an IPv6 address, as long as clients use hostnames instead of IP addresses (and support IPv6) the connection will succeed.

Nice.

Well, @rvp, you have been a marvelous help. Kudos and cheers!

rvp

uxer I mean in the OpenBSD man 4 ip6, IPV6_V6ONLY section there is the word set in the phrase Get or set. This set contradicts read-only (not modifiable) found at the same section.

I think what the man-page is trying to say is that, on OpenBSD, you can call setsockopt with 0 or 1, but, it'll just fail with an error return because IPV6_V6ONLY is read-only.

uxer

https://marc.info/?t=164986437300003&r=1&w=2
https://github.com/qbittorrent/qBittorrent/discussions/16263

The ideal solution would be:

the ideal fix for qbittorrent-nox would be if it created separate socket
bindings, one for IPv4, one for IPv6.

This issue does affect various software in packages, it is a common
thing you need to deal with if you're using various software on OpenBSD.
It doesn't really feel right to me to mention it in a pkg-readme for
one specific package when it affects a wide range of them. Perhaps an
FAQ section might be a better idea.

Still no response from package maintainer, even after Stuart Henderson had sent a patch.