FTP Filter and MSIE3.01? (fwd)
MegaZone (megazone@livingston.com)
Wed, 9 Jul 1997 04:08:17 -0700 (PDT)
Once upon a time Leonard shaped the electrons to say...
> I'm playing around with the filters for PM3 and have a rather intriguing
>case:
> As part of my filter is:
>set filter dialup.in 1 permit 0.0.0.0/0 207.23.43.0/24 tcp dst eq 21
>set filter dialup.in 2 permit 0.0.0.0/0 207.23.43.0/24 tcp dst eq 20
>
> for rulte #2, I also tried:
>set filter dialup.in 2 permit 0.0.0.0/0 207.23.43.0/24 tcp src gt 1023 dst
>eq 20 estab
>
> Both cases work to the point that if I dialin using a win95 client, and
>open a DOS shell and run ftp there, everything works. But if I were to
>use MSIE and try to load as ftp://ftp.mysite.com, it'll "hang" on the
>"loading..." status. On the server side, I can see that the control
>connection succeeded, but not the data socket. This is rather baffling.
>Any ideas?
I believe FTP in both NS and MSIE uses PASV mode. Which, unfortunately,
is not nailed to a particular port. It makes filtering a real joy...
I suspect the DOS FTP program uses the classic FTP connection ports, and
therefore works.
-MZ
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