Sniffing requires collecting packets that aren't addressed to you. Under *normal* circumstances, a switched network will only deliver (a) broadcast traffic, and (b) traffic addressed to your MAC address, to your physical port. You cannot magically reach out through the switch to collect packets sent to other ports.
There are several techniques for getting a switch to send traffic intended for other stations to your port, where your sniffer software can grab it. Some require management access to the switch (and are used routinely by network admins). Some require nasty tricks such as ARP poisoning. All are exceptions to the "*normal*" in the previous paragraph. David Gillett > -----Original Message----- > From: David Wallraff [mailto:[EMAIL PROTECTED] > Sent: June 25, 2003 08:33 > To: Meidinger Christopher > Cc: 'Hilal Hussein'; [EMAIL PROTECTED] Com (E-Mail) > Subject: Re: AW: security-basics Digest 18 Jun 2003 22:09:15 > -0000 Issue > 618 > > > why is it harder to sniff over a switced network? i understand it's > becasue of the switch (natch), but what makes it more difficult? > dave > > > > On Wed, 25 Jun 2003, Meidinger Christopher wrote: > > > Hello Hilal, > > > > Yes, there are many tools that will do that. dsniff, > ettercap, ethereal and > > MANY others will read your password as it goes by on the wire. It is > > slightly more difficult on a switched network, but it can > still be done. > > > > You should not use telnet at all, use ssh (www.openssh.org) > instead. The > > windows client PuTTY is the most common choice to connect > over ssh from > > windows. As far as starting an ssh server on the firewall, > you should be > > able to do that in the same way that you started the telnet server. > > > > If you need more exact help, post to the list what type of > firewall you are > > using, and i am certain someone will help you get started. > > > > (Disclaimer: based on your question, you should [IMHO] > definately read up a > > bit on security before configuring a firewall) > > > > badenIT GmbH > > System Support > > > > Chris Meidinger > > Tullastrasse 70 > > 79108 Freiburg > > > > > > -----Ursprüngliche Nachricht----- > > Von: Hilal Hussein [mailto:[EMAIL PROTECTED] > > Gesendet: Tuesday, June 24, 2003 10:08 AM > > An: [EMAIL PROTECTED]; [EMAIL PROTECTED] > > Betreff: Re: security-basics Digest 18 Jun 2003 22:09:15 > -0000 Issue 618 > > > > > > > > > > Hello All, > > > > i am not sure if i am asking the right question within the > same subject,but > > i am configuring the firewall throught the telnet > connecting / from winxp > > workstation. > > > > Is there any possibility for any internal user to use any > tools that will > > haijack my telnet password - password for the firewall > too!, and what are > > the measurements for securing the telnet session. > > > > with regards, > > Hilal Hussein > > > > _________________________________________________________________ > > STOP MORE SPAM with the new MSN 8 and get 2 months FREE* > > http://join.msn.com/?page=features/junkmail > > > > > > > -------------------------------------------------------------- > ------------- > > Evaluating SSL VPNs' Consider NEOTERIS, chosen as leader by > top analysts! > > The Gartner Group just put Neoteris in the top of its Magic > Quadrant, > > while InStat has confirmed Neoteris as the leader in marketshare. > > > > Find out why, and see how you can get plug-n-play secure > remote access in > > about an hour, with no client, server changes, or ongoing > maintenance. > > > > Visit us at: http://www.neoteris.com/promos/sf-6-9.htm > > > -------------------------------------------------------------- > -------------- > > > > > -------------------------------------------------------------- > ------------- > > Evaluating SSL VPNs' Consider NEOTERIS, chosen as leader by > top analysts! > > The Gartner Group just put Neoteris in the top of its Magic > Quadrant, > > while InStat has confirmed Neoteris as the leader in marketshare. > > > > Find out why, and see how you can get plug-n-play secure > remote access in > > about an hour, with no client, server changes, or ongoing > maintenance. > > > > Visit us at: http://www.neoteris.com/promos/sf-6-9.htm > > > -------------------------------------------------------------- > -------------- > > > > > > -------------------------------------------------------------- > ------------- > Evaluating SSL VPNs' Consider NEOTERIS, chosen as leader by > top analysts! > The Gartner Group just put Neoteris in the top of its Magic Quadrant, > while InStat has confirmed Neoteris as the leader in marketshare. > > Find out why, and see how you can get plug-n-play secure > remote access in > about an hour, with no client, server changes, or ongoing maintenance. > > Visit us at: http://www.neoteris.com/promos/sf-6-9.htm > -------------------------------------------------------------- > -------------- > --------------------------------------------------------------------------- Evaluating SSL VPNs' Consider NEOTERIS, chosen as leader by top analysts! 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