Ethical Hacking

Learn to find vulnerabilities before the bad guys do! Gain real world hands on hacking experience in our state of the art hacking lab. Course designed and taught by expert instructors with years of penetration testing experience. 12 student maximum in every class. Certification attempt included in every package.
Computer Forensics Training at InfoSec Institute

Gain the in-demand skills of a certified computer examiner, learn to recover trace data left behind by fraud, theft, and cybercrime perpetrators. Discover the source of computer crime and abuse at your organization so that it never happens again. All of our class sizes are guaranteed to be 12 students or less to facilitate one-on-one interaction with one of our expert instructors.




Network Security Firewalls
[Top] [All Lists]

PIX and PASV ftp

Subject: PIX and PASV ftp
Date: Tue, 19 Jul 2005 12:34:31 -0700
I'm having some difficulty in getting the PIX to allow PASV connections
through.  I have a vsftpd server on a DMZ with a private IP and running
IPTables with modules ip_nat_ftp and ip_conntrack_ftp loaded, though
same errors occur with IPTables stopped.  The vsftpd server has a
pasv_address of the public IP, and pasv_enable is YES.

The error from IE browser is "An error occurred opening that folder on
the FTP Server. Make sure you have permission to access that folder."

Ethereal on the client follows the TCP stream like this:
220 Welcome message nnnn
USER xxxxx
331 Please specify the password.
PASS xxxxx 
230 Login successful. Have fun. 
SYST 
215 UNIX Type: L8 
FEAT 
500 Unknown command. 
TYPE I
200 Switching to Binary mode. 
REST 0 
350 Restart position accepted (0). 
PWD 
257 "/home/xxxx" 
PASV 
<then a bunch of TCP Retransmission requests for PASV>

The server log shows it responds to the PASV command with:
<Time/date> <pid> <username> FTP command: Client "nnn.nnn.nnn.nnn",
"PASV"
<Time/date> <pid> <username> FTP response: Client "nnnnnn", "227
Entering Passive Mode (nnn,nnn,nnn,nnn,190,130)"
But the client never gets that message.

The pix logs this:
"%PIX-4-406002: FTP port command different address: from
<outsideIP:port> to <insideIP:port>".
"%PIX-6-302014: Teardown TCP connection nnn for outside:<outsideIP:port>
to dmz:<insideIP:port> duration 00:00:01 bytes 350 Deny".
"PIX-6-106015: Deny TCP (no connection) from <outsideIP:port> to
<insideIP:port>".

Non-PASV works fine.

I'm worn out Googling this.  Has anyone experienced this before?

Thanks,
Bill Stout
www.greenborder.com


<Prev in Thread] Current Thread [Next in Thread>