IPv6 addresses in configuration is not parsed, and result in an error

[rpc-scandinavia]

Prerequisites

• I have searched for duplicate or closed issues
• I can recreate the issue with all plugins disabled

Describe the issue

I am testing the new RCM version 1.7 RC4 and configure SQL using an IPv6 address like [fd00:3::10], but RCM can't parse those and fails with the Oops screen.

This is configured in config.inc.php for SQL:

$config['db_dsnw'] = 'pgsql://user:password@[fd00:3::11]/roundcubemail';
$config['db_dsnw'] = 'pgsql://user:password@10.10.3.11/roundcubemail';

The first connection string don't work, the second connection string does work (used one at a time).

This was originally fixed for MariaDB in bug report #9937.
In this bug report, I am using PostgreSQL.

What browser(s) are you seeing the problem on?

Firefox

What version of PHP are you using?

8.4.16

What version of Roundcube are you using?

1.7 RC4

JavaScript errors

None.

PHP errors

[03-Mar-2026 15:44:48 +0000]: <3a755022> DB Error: SQLSTATE[08006] [7] connection to server at "[fd00:3::11]", port 5432 failed: timeout expired in /opt/roundcubemail/1.7-rc4/program/lib/Roundcube/rcube_db.php on line 186 (GET /)

[alecpl]

Are you suggesting we should not use brackets or what? I see the IP is correct in the error message. Can you connect using this IP address in postgres CLI?

[rpc-scandinavia]

No, I think that the IPv6 address isn't parsed correctly or used correctly.
Perhaps the brackets should be trimmed, since PSQL command don't want them.

Correct IPv6 address fail:

$config['db_dsnw'] = 'pgsql://user:password@[fd00:3::11]/roundcubemail';

$ cat errors.log 
[09-Mar-2026 19:24:30 +0000]: <b5e8dc1d> DB Error: SQLSTATE[08006] [7] connection to server at "[fd00:3::11]", port 5432 failed: timeout expired in /opt/roundcubemail/1.7-rc2/program/lib/Roundcube/rcube_db.php on line 186 (GET /)

Incorrect IPv6 without brackets fail:

$config['db_dsnw'] = 'pgsql://user:password@fd00:3::11/roundcubemail';

$ cat errors.log 
[09-Mar-2026 19:26:15 +0000]: <b5e8dc1d> DB Error: SQLSTATE[08006] [7] connection to server at "fd00", port 3 failed: timeout expired in /opt/roundcubemail/1.7-rc2/program/lib/Roundcube/rcube_db.php on line 186 (GET /)

IPv4 address succeeds:

$config['db_dsnw'] = 'pgsql://user:password@10.10.3.11/roundcubemail';

PSQL succeeds without brackets:

$ psql  --host=fd00:3::11  --username=user  --dbname=roundcubemail
Password for user roundcubemail: 
psql (17.7 (Debian 17.7-0+deb13u1))
Type "help" for help.

roundcubemail=> \d
roundcubemail=> exit

PSQL fails with brackets:

$ psql  --host=[fd00:3::11]  --username=user  --dbname=roundcubemail
psql: error: connection to server at "[fd00:3::11]", port 5432 failed: Connection timed out
        Is the server running on that host and accepting TCP/IP connections?

Yes my theory seems to be correct.
I made this change to /program/lib/Roundcube/rcube_db.php at line 172:

//$this->dbh = new \PDO($dsn_string, $username, $password, $dsn_options);
$this->dbh = new \PDO("pgsql:host=fd00:3::11;dbname=roundcubemail", $username, $password, $dsn_options);

And this works.
If I add the brackets, it fails as in the first example in this post.
So it looks like the IPv6 brackets need to be striped from the host part of the $dsn_string, to accommodate this feature of the PostgreSQL provider.

[alecpl]

On the other hand I can find some information about MySQL driver requiring the brackets. https://bugs.php.net/bug.php?id=74557. This may be PHP version dependent, but it would be nice if MySQL accepted also non-bracket input. If that would be the case for PHP >= 8.1 we could treat postgres and mysql the same.

[rpc-scandinavia]

Yes @alecpl, everyone should follow the standard for IPv6 with is with brackets.

The psql command is a Perl script. Perhaps it is a thing in the PostgreSQL world, not to use IPv6 brackets.

So the MySQL connector developers did the right thing.

RFC 3986 section 3.2.2

A host identified by an Internet Protocol literal address, version 6 [RFC3513] or later, is distinguished by enclosing the IP literal within square brackets ("[" and "]"). This is the only place where square bracket characters are allowed in the URI syntax. In anticipation of future, as-yet-undefined IP literal address formats, an implementation may use an optional version flag to indicate such a format explicitly rather than rely on heuristic determination.

   IP-literal = "[" ( IPv6address / IPvFuture  ) "]"

   IPvFuture  = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )

[alecpl]

Brackets are necessary when you have to specify port number together with the host ([::1]:3306), but PDO DSN strings separate host and port so using brackets shouldn't be needed. That being said, seems the fix will be to always trim the brackets, but for MySQL add them in rcube_db_mysql::dsn_string().

[rpc-scandinavia]

but for MySQL add them in

Yes that is a good point, you should probably revisit bug report #9937 and be sure to add the brackets if they are missing.