[PLUG] Resolver going to DNS for private IP reverse lookups, flagrantly ignoring /etc/hosts?

[Ian Burrell]

Randall Lucas wrote:
> 
> wu-ftpd seemed to be intractably using DNS for reverse lookups, ignoring 
> hosts.  I think this problem was covered up before because my upstream 
> DNS provider was quickly failing on the private IP reverse lookup, but 
> must have changed their config so that ~ 10% or so of the time it slowly 
> fails.
> 
> My workaround was to install vsftpd in standalone (listen=YES) mode, 
> which seemed to solve the problem.  I don't know if vsftpd just doesn't 
> bother with reverse lookup, or if it uses /etc/hosts, but either way, 
> FTP once again answers speedily.
> 

One problem I have run into with wu-ftpd is that it tries to do an ident 
lookup on the incoming connection so it can log the username that is 
connecting.  Except ident is rarely used any more and doesn't give 
reliable information.  It just slows things down especially when the 
connection is firewalled.  There is an option to wu-ftpd, -I, that turns 
this off.  With xinetd, it can be added to server_args line in the 
/etc/xinetd.d/wu-ftpd file.

vsftpd is a better FTP server in any case.

  - Ian

-- 
ian at znark.com
http://www.znark.com/