Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!ecngs!feeder2.ecngs.de!newsfeed.freenet.ag!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.088 X-Spam-Evidence: '*H*': 0.82; '*S*': 0.00; 'subject:Python': 0.05; 'nasty': 0.07; 'do,': 0.15; 'all?': 0.16; 'for,': 0.16; 'from:addr:rosuav': 0.16; 'from:name:chris angelico': 0.16; 'printout': 0.16; 'roy': 0.16; 'wrote:': 0.17; 'detect': 0.17; 'thus': 0.24; 'header:In-Reply-To:1': 0.25; 'am,': 0.27; 'message- id:@mail.gmail.com': 0.27; "doesn't": 0.28; 'firewall': 0.29; 'though.': 0.29; "i'm": 0.29; '(and': 0.32; "aren't": 0.33; 'messages,': 0.33; 'to:addr:python-list': 0.33; 'knowledge': 0.33; 'presence': 0.33; 'another': 0.33; 'received:google.com': 0.34; 'nov': 0.35; 'expected': 0.35; "won't": 0.35; 'received:209.85': 0.35; 'really': 0.36; 'but': 0.36; 'should': 0.36; 'subject: (': 0.36; 'being': 0.37; 'drop': 0.37; 'received:209': 0.37; 'subject:: ': 0.38; 'sure': 0.38; 'to:addr:python.org': 0.39; 'notice': 0.39; 'subject:-': 0.40; 'header:Received:5': 0.40; 'enable': 0.60; 'most': 0.61; 'back': 0.62; 'referred': 0.62; 'necessarily': 0.63; 'more': 0.63; 'to,': 0.65; 'smith': 0.71; 'article': 0.78; 'common,': 0.84; 'firewalls': 0.84; 'exceeded': 0.97 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=ND8E2fK/l4oYwF5xVR/NlhJik5OYvRUofHQn4hKckM4=; b=nfpWANwTh4gbLc5kbETsG5n5xP7pPBBaJNtXoRbgepa27pXK3lxiuXjdrEs0Tt7t75 VPClI6ZeDdMVipQvRp9pnEOe581NRj6M5Y2rEajR+MSDtKr+TPTQN+uiRxba2La3np/U wzPT1iYxbHx6l0/nuQ1C3Gcy3QlrAm4sV+JdlY8xaRKvuB7BPhaWkhk1o1KojFiR2FUh vdP8+9mG97mmwye+9MU/Z2v6zEXQrRHy23f6339GVctU05aK+R5ra1mq2XEvrsyM/2A3 8UKR/HgCnVkys2+Hov6ZTsOUwTGGSr+oBGzNe1/5HOYC1UrkrzUDiNMf3TK8MN6Y895L I7Sg== MIME-Version: 1.0 In-Reply-To: References: <6ea528f6-e4c2-4da9-a011-d81f13b83d28@googlegroups.com> Date: Sun, 18 Nov 2012 05:45:57 +1100 Subject: Re: Python Script for Colorizing Traceroute Output (apologies for top-post) From: Chris Angelico To: python-list@python.org Content-Type: text/plain; charset=ISO-8859-1 X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 20 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1353177966 news.xs4all.nl 6934 [2001:888:2000:d::a6]:53069 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:33480 On Sun, Nov 18, 2012 at 5:38 AM, Roy Smith wrote: > In article , > wrw@mac.com wrote: >> Don't forget that most firewalls don't decrement) the time-to-live number, >> and unless you REALLY know what to look for, are invisible. > > Interesting. If the firewall doesn't decrement TTL (a particular nasty > thing to do, and thus completely expected of a firewall) what REALLY > knowledge would enable you to detect its presence in a traceroute > printout at all? If it's a router, then it definitely should be decrementing TTLs, though if the firewall is simply a part of another hop, you won't notice it specifically. What's more common, though, is devices that decrement TTL and drop packets but don't send back Time Exceeded messages, giving the classic "* * *" line. I'm not sure if that's what was being referred to, though. (And they aren't necessarily firewalls.) ChrisA