Subject: Re: WU-ftpd Un-official Patches

From: [email-masked] (Rob Hewlett)
Date: Fri, 21 Jul 1995 12:09:49 +0100

>I'm seriously interested in having a system which responds differently
>depending upon which network interface is used to get into the system.
>For example, when ftping to 1.2.3.4, you would appear to reach a host
>called "xxx.com", while going to 1.2.4.5 you get "yyy.gov".  I remember
>seeing discussion of this fairly recently.

I've just set that exact process up with a program called TCP Wrappers.  It
allows you to look for origin or destination addresses and act upon them.
It basically sits between inetd and whatever daemon program you will be
running (it works for telnet and WWW too).  Basically, you have to compile
different
wu-ftpd if you would like to change the options for each system (for example, 
I changed several directories, and changed the chroot() command for each
instance of the program I am running).  Then I configured TCP Wrappers to
run different daemons depending upon the address of the ftp request(there
was also and ifconfig in there somewhere to set up an alias for the machine).

Hope that was what you were looking for.

-Rob

---

From: "Kevin W. Mullet" <[email-masked]>
Date: Fri, 21 Jul 1995 11:38:03 -0500 (CDT)

Okay -- everyone knows that having one machine that can respond
differently to URLs like http://alpha.com/ and http://bravo.com/ is a
good thing, and that it can't just be done with DNS CNAMEs.

The quoted message below is from the Washington University FTP Daemon
mailing list, wu-ftpd.  It seems to indicate that you can make this
happen with TCP-Wrapper.  Previously, I'd gotten a URL from Prentiss,
<http://www.thesphere.com/%7Edlp/TwoServers/>, that documented another
approach.

What would be the difference between having destination-address
sensitive HTTP, FTP (or, hmmmm... in.telnetd...) daemons using
TCP-Wrapper and using one of the methods (interface aliasing with
ifconfig, or defining numerous routing PPP interfaces) described at URL
<http://www.thesphere.com/%7Edlp/TwoServers/>?

Am I missing something here?  It seems like TCP Wrapper is the better
solution, 'cause you get to install more security on your machine as
well.  Wait -- maybe I am missing something.  TCP Wrapper can't possibly
make your machine respond to additional IP addresses, right?  You've
still got to do the http://www.thesphere.com/%7Edlp/TwoServers/ thing to
make the IP address work on a given interface, but once that address
works, then, I guess, your choice is to either use patched daemons (or
daemons that are smart enough to be used with virtual interfaces) or use
TCP Wrapper to mediate the access.

Do I appear to have a moderately clear understanding of this issue? Any
obvious lack of clue?

cheers,
-KwM-

oh -- btw, Cathy.  My condolences on becoming sole support of the world.

[...]
>From [email-masked] Fri Jul 21 11:12:04 1995
>Date: Fri, 21 Jul 1995 12:09:49 +0100
>From: [email-masked] (Rob Hewlett)
>To: [email-masked]
>Subject: Re: WU-ftpd Un-official Patches
>