I have a wifi shared connection with other flatmates and I'd like to know how can I protect my Debian pc from being sniffed. Should I use a wifi anti sniffer to detect if any wifi card is in promiscuous mode? in that case it's only to detect, but if no wifi cards are in promiscuous mode means that nobody is sniffing right? In the case that someone is sniffing, would be the only solution the use of a VPN to protect my packets? or is there another way to protect from sniffing?

  • Please clarify your 3rd sentence. – dan Aug 11 '14 at 13:05

Should I use a wifi anti sniffer...?

These work by detecting responses from the sniffing card - it's not hard to prevent any packets being sent out.

would be the only solution the use of a VPN to protect my packets?

This doesn't stop the packets from being sniffed - it only prevents them from being read or modified. As such it's no different from other forms of encryption (e.g. SSH, SSL). You also need an end point for the VPN before you can access any services outwith the VPN. If you don't trust the people you live with, do you trust the people who manage the VPN end point? Although many routers have VPN capabities I've only ever seen this for the internet facing side - not the LAN side - so unless you know differently your only practical solution to the problem is to build your own router with VPN, DHCP, NAT.

  • actually is just a way to learn security, I have nothing to hide to my flatmates, but it's good to know how to protect from this kind of situations. I didn't understand the first answer, you say that there is a way to avoid an anti sniffer? And regarding the second answer, maybe using a vpn would be a good choice – nelson687 Feb 3 '14 at 12:17
  • that is what I was thinking, using only ssh in the pages that supports, is enough isn't it? – nelson687 Feb 13 '14 at 10:23
  • → Nelson: the 1st part of this answer means that anti-sniffer is sneak oil. It is very easy for any network sniffer to avoid sending any packet on the network. – dan Aug 11 '14 at 13:03
  • @symcbean I don't quite agree that a VPN tunnel (or SSH tunnel) would not protect the OP from disclosing who they talk to. So long as all their traffic goes through the tunnel and is encrypted, how would a sniffer be able to see who some traffic is directed to? They'd only be able to find out the address of the tunnel endpoint? – Steve Dodier-Lazaro Aug 11 '14 at 13:14
  • @Steve DL: read my post again. If the VPN end point is controlled by the person you're trying to hide information from then it is not fit for purpose. If the sniffer cannot access the end points then won't have direct access to the content of the packets however they will be see that the packets exist and the MAC addresses - and if they can see an unencrypted upstream then they can easily establish a correlation between the remote end point on the unencrypted network and the MAC address within the VPN. – symcbean Aug 11 '14 at 14:16

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