From owner-freebsd-questions@freebsd.org Tue Jun 18 16:50:31 2019 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1264315C2A79 for ; Tue, 18 Jun 2019 16:50:31 +0000 (UTC) (envelope-from johnl@iecc.com) Received: from gal.iecc.com (gal.iecc.com [IPv6:2001:470:1f07:1126:0:43:6f73:7461]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "gal.iecc.com", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7DF8685216 for ; Tue, 18 Jun 2019 16:50:30 +0000 (UTC) (envelope-from johnl@iecc.com) Received: (qmail 67583 invoked from network); 18 Jun 2019 16:50:29 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=iecc.com; h=date:message-id:from:to:subject:mime-version:content-type:content-transfer-encoding; s=107fb.5d091655.k1906; i=johnl-iecc.com@submit.iecc.com; bh=owmSGEubJ/Jefx0P8IqKYO6WBVRRT9vdhktIHcSEDCc=; b=r+j1isViTgqdRWy7FL9nIJFOOUITAv/tYLKHeZecuSuUSxUDT8Zrj2N/qaSkvhLfy4R4T0wF9DeAJchX57Q9fzeuGJlBC8HorKkqwGP1anUnWasF8MD5T6Zm9wUF2tNqXEIw5mDQVBr9Nat41+vu2wH4hO+GGeKwoVSCO8amgxm6Xoy+10sj+L9RMJ3oX0pKQzXrZxWT7T+qD3n3AByady9Bcz+udiplPxXC49ZLWtgpLRvd4Sa9PrafXoXVsN/n Received: from ary.qy ([64.246.232.221]) by imap.iecc.com ([64.57.183.75]) with ESMTPSA (TLS1.2 ECDHE-RSA AES-256-GCM AEAD, johnl@iecc.com) via TCP; 18 Jun 2019 16:50:28 -0000 Received: by ary.qy (Postfix, from userid 501) id 83C662015F9118; Tue, 18 Jun 2019 12:50:27 -0400 (EDT) Date: 18 Jun 2019 12:50:27 -0400 Message-Id: <20190618165028.83C662015F9118@ary.qy> From: "John Levine" To: freebsd-questions@freebsd.org Subject: IPFW redirect to another port? Organization: Taughannock Networks X-Headerized: yes Mime-Version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 8bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Jun 2019 16:50:31 -0000 I would like to use ipfw to redirect incoming port 53 requests from a few IP addresses to a different port, so I can use a custom DNS server to answer them. I can figure out how to redirect their traffic to, say, port 5553, but the responses come from 5553 which of course doesn't work. Any suggestions about how to adjust the port numbers going both ways? It's fine if they screw up other traffic to those IPs. TIA.