Subject: how to set up FTP and DNS server behind fwtk box

From: "wen" <[email-masked]>
Date: Mon, 11 Dec 2000 17:15:10 +0800

hi,everyone:
    I have installed fwtk2.1 in my system box which was installed redhat6.1. now I want to set up FTP sever and DNS server behind fwtk box. I have tried next:
in my net-perm file I add 
        plug-gw: port 21 * -plug-to port 21   my-ftp-server.ip
        plug-gw1:port 20  * -plug-to port 20   my-ftp-server.ip
for DNS server
        plug-gw2: port 53 * -plug-to port 53 my-DNS-server.ip

I have changed plug-gw.c in order to make plug-gw daemon which only kowns plug-gw prefix  kowns above rule prefix.

but now ftp server and DNS server don't work. why?

here I think when ftp is working port 20 and 21 are correspond,but plug-gw daemon can not do with these. for DNS server,it is the same problem,becanse DNS server need tcp port 53 and udp port 53.
but I do not know how to do to resolv this problem. some advice appreciate.

---

From: Rick Murphy <[email-masked]>
Date: Mon, 11 Dec 2000 06:15:05 -0500

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At 05:15 PM 12/11/00 +0800, wen wrote:
>hi,everyone:
>     I have installed fwtk2.1 in my system box which was installed 
> redhat6.1. now I want to set up FTP sever and DNS server behind fwtk box. 
> I have tried next:

There are two problems with your setup.
FTP uses destination port 21 for it's control connection, but it uses 
*source* port 20 for the data connection (by default). To connect to a ftp 
server, you must use ftp-gw since ftp-gw understands the ftp protocol.
There is a patch (if I remember correctly) for ftp-gw to permit you to 
force the destination address to a single ftp server.

DNS usually uses UDP port 53 for name queries (TCP is used only for queries 
that return a large number of names, but UDP 53 dominates.)
You can't use plug-gw to forward UDP.
Typically, people run their externally-visible DNS on the firewall. If you 
must run an internal DNS server, set up a ipchains rule on your firewall to 
permit forwarding UDP port 53 to the DNS server.
         -Rick