Great Circle Associates Firewalls
(April 1996)
 

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Subject: Re: Filtering by Source Port
From: scott @ zorch . sf-bay . org (Scott Hazen Mueller)
Organization: At Home; Salida, CA
Date: Tue, 23 Apr 1996 14:01:04 GMT
Apparently-to: firewalls @ greatcircle . com
Distribution: zorch
Newsgroups: zorch.lists.firewalls
References: <199604221540 . IAA21891 @ dfw-ix7 . ix . netcom . com>
Reply-to: scott @ zorch . sf-bay . org

>>ps. When I talked to Cisco Tech Support they couldn't understand why anyone
>>would even want to filter by source port.

>I don't understand why you would want to filter by source port either.  

Given x.y.z.0 as your internal network:

access-list 101 permit tcp any eq ftp-data x.y.z.0 gt 1023

It's sure not perfect, but if you don't have an active gateway, it's a tiny
bit better than just allowing random TCP connections to internal high ports.

-- 
Scott Hazen Mueller | scott @
 zorch .
 SF-Bay .
 ORG or tandem!zorch!scott



References:
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