Bug#620871: EPRT for IPv4 fails with IPv6 enabled server.

[Hilmar Preuße]

Am 04.04.2011 um 21:46 schrieb Mats Erik Andersson:

Dear Mats,

> Package: proftpd-basic
> Version: 1.3.3a-6squeeze1
> Severity: normal
> Tags: ipv6 upstream

That bug was filed years ago against an old version. Are you still able 
to reproduce the problem? Sorry for the long response time!

> When using the IPv6-enabled server (and 'net.ipv6.bindv6only = 0')
> an IPv4-only client will get a positive/successful response to
> an EPRT command. However, the connection fails, because the server
> is establishing an IPv6 socket at ':ftp-data', not the expected
> IPv4 socket. The exchange goes like this:
>
>   > ls
>   200 EPRT command successful
>   425 Unable to build data connection: Invalid argument
>
>
> After reconfiguring the server to be IPv4-only, the EPRT is fully
> functional, as is to be expected.
>
> The proftpd-server was freshly installed for the purpose of testing
> different clients, so besides the setting "UseIPv6" nothing was
> ever changed in the configuration.
>
> At the moment I can trigger this error using a patched FTP client
> from GNU Inetutils. Since this patching works correctly against
> the OpenBSD FTP server (with PASV, EPSV, LPSV, PORT, EPRT, LPRT),
> I am personally convinced that the error lies in 'poftpd/modules/mod_core.c'.
>
> Granted some time I might be able to craft a Perl client to also
> trigger this error.
>


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