Blocking port automatically

[Ashley M. Kirchner]

    I have to run a public FTP server for our clients to upload files to 
us.  This means that every day I have to deal with some machine, usually 
in Asia but occasionally also here in the States, banging on the ftp 
port several times a second, trying to log in with various (invalid) 
user names.  For example this morning:

Feb 17 07:47:13 lansky vsftpd: pam_succeed_if(vsftpd:auth): error 
retrieving information about user Administrator
Feb 17 07:47:16 lansky vsftpd: pam_unix(vsftpd:auth): check pass; user 
unknown
Feb 17 07:47:16 lansky vsftpd: pam_unix(vsftpd:auth): authentication 
failure; logname= uid=0 euid=0 tty= ruser= 
rhost=216.31.131.61.broad.dynamic.pt.fj.cndata.com
Feb 17 07:47:16 lansky vsftpd: pam_succeed_if(vsftpd:auth): error 
retrieving information about user Administrator
Feb 17 07:47:19 lansky vsftpd: pam_unix(vsftpd:auth): check pass; user 
unknown
Feb 17 07:47:19 lansky vsftpd: pam_unix(vsftpd:auth): authentication 
failure; logname= uid=0 euid=0 tty= ruser= 
rhost=216.31.131.61.broad.dynamic.pt.fj.cndata.com
Feb 17 07:47:19 lansky vsftpd: pam_succeed_if(vsftpd:auth): error 
retrieving information about user Administrator
Feb 17 07:47:22 lansky vsftpd: pam_unix(vsftpd:auth): check pass; user 
unknown
Feb 17 07:47:22 lansky vsftpd: pam_unix(vsftpd:auth): authentication 
failure; logname= uid=0 euid=0 tty= ruser= 
rhost=216.31.131.61.broad.dynamic.pt.fj.cndata.com


    Is there a way to configure iptables to automatically block a 
specific IP after a certain repeated count (in a specific period)?  Or, 
is there a way to tell vsftpd to deny connections after a certain number 
of failed logins?  Something like a MaxLoginAttempts or some such?

-- 
H | It's not a bug - it's an undocumented feature.
  +--------------------------------------------------------------------
  Ashley M. Kirchner <mailto:ashley at pcraft.com>   .   303.442.6410 x130
  IT Director / SysAdmin / Websmith             .     800.441.3873 x130
  Photo Craft Imaging                       .     3550 Arapahoe Ave. #6
  http://www.pcraft.com ..... .  .    .       Boulder, CO 80303, U.S.A.