Ahoi,
At [1] I can read "All extensions except vendorID and xattr are enabled
by default." The page reports more extensions, than these from your log
file, e.g. limits. I'm not sure if the log is complete.
I'm not sure, how the release and the documentation fit each other,
since 1.3.8 won't accept "userGroupNames".
```
2026-03-23 11:43:39,874 test-vm3 proftpd[66933]: fatal: SFTPExtensions:
unknown extension: 'userGroupNames' on line 13 of '/etc/proftpd/sftp.conf'
```
Testing against 1.3.9 from debian testing, as suggested, the list looks
way more complete. See below.
>> When using paramiko.sftp_file.SFTPFile.check anyways - the request
>> won't be accepted:
>>
>
> I guess this your proof that, that the extension is really not
> activated, right?
Yes this was my intention. But testing against 1.3.9 it did not work
either. So I've tested again using bitvise ssh client - proftpd
calculates checksums as intended. Works even in 1.3.8 as in trixie,
though not listing the feature.
So no issue here.
Thanks for pointing into the right direction.
Best, Joerg
```
2026-03-23 09:35:59,220 [1572] <sftp:7>: received request: INIT 3
2026-03-23 09:35:59,220 [1572] <sftp:8>: sending response: VERSION 3
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension: versions =
'2,3,4,5,6'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension: check-file = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension: copy-file = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
home-directory = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
space-available = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension: vendor-id =
{ vendorName = 'ProFTPD Project', productName = 'mod_sftp',
productVersion = 'mod_sftp/1.2.0', buildNumber = 16976132 }
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '2'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '2'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <sftp:11>: + SFTP extension:
[email protected] = '1'
2026-03-23 09:35:59,220 [1572] <encode:5>: decoded 'INIT' into 'INIT'
```
Before opening a bug at upstream: do you have an unstable installation
running 1.3.9 and could test if the issue is solved there? If needed I
can provide backports for Debian stable.
Hilmar
[1] http://www.proftpd.org/docs/contrib/mod_sftp.html#SFTPExtensions
