how to deny someone to use ftp command ? Post: 302148846

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Special Forums IP Networking how to deny someone to use ftp command ? Post 302148846 by yarx on Monday 3rd of December 2007 11:42:03 PM

12-04-2007

Registered User

Quote:

Originally Posted by Smiling Dragon

You'll never be able to fully prevent users from running ftp to an uncontrolled remote host but you can make it harder by restricting connections on port 21 from AAA to BBB. It's not a prefect solution though as an ftpd can be run on any port, a determined user will just move the ftpd and carry on doing it.

However, in 90% of the cases where I hear these sorts of questions, it actually the wrong question being asked. Are you sure this is the correct solution to your problem? Why do you want to prevent the ftp in the first place? Why is BBB being targeted as a server to prevent access to?

If you are trying to prevent users from using the system for unathorised purposes (eg it's a school computer perhaps), it might be better to define what is acceptable and what is not, then perform 'after the fact' auditing and clobber whoever did it Smilie

It's a matter of human nature, if we see a fence, we try and go over it. Making a stronger fence only encourages us to try harder. If we get attacked by a bull in the paddock, we'll probably think twice about climbing that fence next time no matter how easy it was to get past...

hi,Smiling Dragon,thanks for your reply.

if BBB open port 21/20 to transfer the data from AAA, i can use "iptables"(on linux, or any others software like have a firewall functions) to drop the data package, like you saied " It's not a prefect solution though as an ftpd can be run on any port ".

i think is the wrong question to ask someone. Smilie

yarx

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LEARN ABOUT CENTOS

ftphosts

ftphosts(4)							   File Formats 						       ftphosts(4)

NAME

       ftphosts - FTP Server individual user host access file

SYNOPSIS

       /etc/ftpd/ftphosts

DESCRIPTION

       The ftphosts file is used to allow or deny access to accounts from specified hosts. The following access capabilities are supported:

       allow username addrglob [addrglob...]

	   Only allow users to login as username from host(s) that match addrglob.

       deny username addrglob [addrglob...]

	   Do not allow users to login as username from host(s) that match addrglob.

       A username of * matches all users. A username of anonymous or ftp specifies the anonymous user.

       addrglob  is  a	regular  expression that is matched against hostnames or IP addresses. addrglob may also be in the form address:netmask or
       address/CIDR, or be the name of a file that starts with a slash ('/') and contains additional address  globs.  An  exclamation  mark  (`!')
       placed before the addrglob negates the test.

       The first allow or deny entry in the ftphosts file that matches a username and host is used. If no entry exists for a username, then access
       is allowed. Otherwise, a matching allow entry is required to permit access.

EXAMPLES

       You can use the following ftphosts file to allow anonymous access from any host except those on the class A network 10, with the  exception
       of 10.0.0.* IP addresses, which are allowed access:

       allow   ftp   10.0.0.*
       deny    ftp   10.*.*.*
       allow   ftp   *

       10.0.0.* can be written as 10.0.0.0:255.255.255.0 or 10.0.0.0/24.

FILES

       /etc/ftpd/ftphosts

ATTRIBUTES

       See attributes(5)  for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWftpr			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |External			   |
       +-----------------------------+-----------------------------+

SEE ALSO

	in.ftpd(1M), ftpaccess(4), attributes(5)

SunOS 5.10							    1 May 2003							       ftphosts(4)

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