[jira] Commented: (NET-313) FTP: EPRT fails + EPRT/EPSV issues

["Mirko Nasato (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/NET-313?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12873680#action_12873680 ] 

Mirko Nasato commented on NET-313:
----------------------------------

Just stumbled into an issue with v2.1 and nf_conntrack_ftp on Linux where the connection times out and iptables logs something like

  May 31 14:16:38 foo kernel: [35656.336325] conntrack_ftp: partial EPRT 987422914+27

I guess this may confirm your IPv6 "could even have disadvantages" prediction. Using commons-net v2.0 everything works fine.

(I also wonder why there are v2.1 jars in the Maven central repository if v2.1 hasn't been officially released yet, but that's a different story.)


> FTP: EPRT fails + EPRT/EPSV issues
> ----------------------------------
>
>                 Key: NET-313
>                 URL: https://issues.apache.org/jira/browse/NET-313
>             Project: Commons Net
>          Issue Type: Bug
>    Affects Versions: 2.1
>         Environment: FTP server = vsftpd/Centos 5.4
> FTPClient = commons-net (FTPClient) ;)
> Network = IPv4
>            Reporter: Felix Bolte
>         Attachments: ftp_nat.patch
>
>
> as implemented in NET-288, the client can work now via IPv6 ... EPSV is not only useful on IPv6 but also when NAT is enabled (see [RFC 2428|http://tools.ietf.org/html/rfc2428])
> what my patch does:
>  * (re)enable EPSV command on IPv4 too (i dont know why [~rwinston@eircom.net] removed it from the supplied patch in NET-288), also see my comments in patch
>  * sending EPRT only if we are over IPv6, cause there is no advantage over PORT on IPv4, it could even have disadvantages (see comments in patch)
>  * EPRT was sending the result of getActivePort() to the server, but when there was no activePortRange set, it did send 0 as default which leads to an error on server site:
> {quote}
> Tue Mar 23 17:17:20 2010 [pid 10581] [ftpuser] FTP command: Client "192.168.11.130", "EPRT |1|192.168.11.130|0|"
> Tue Mar 23 17:17:20 2010 [pid 10581] [ftpuser] FTP response: Client "192.168.11.130", "500 Illegal EPRT command."
> {quote}
>  * and even calling getActivePort() has no sense here, cause that port is used to be random, but we should send same port  where the ServerSocket is listening on -> server.getLocalPort()
>  * getActivePort() checks if __activeMaxPort > __activeMinPort, but when i want to set a range of only one single port (min==max) it would return 0 ... now it will check if equal and return __activeMaxPort

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