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Groups > linux.debian.user > #157063
| From | Brian <ad44@cityscape.co.uk> |
|---|---|
| Newsgroups | linux.debian.user |
| Subject | Re: laptop protection in an office network |
| Date | 2015-08-29 21:10 +0200 |
| Message-ID | <q2TFM-2lh-7@gated-at.bofh.it> (permalink) |
| References | (3 earlier) <q2IAG-3ek-7@gated-at.bofh.it> <q2JwJ-4yL-5@gated-at.bofh.it> <q2MXE-Td-9@gated-at.bofh.it> <q2T34-1mE-3@gated-at.bofh.it> <q2TcK-1y2-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Sat 29 Aug 2015 at 21:39:21 +0300, Reco wrote: > Hi. > > On Sat, 29 Aug 2015 13:25:28 -0500 > rlharris@oplink.net wrote: > > > On Sat, August 29, 2015 6:53 am, tomas@tuxteam.de wrote: > > > Also netstat (issued from your laptop) gives insight. For example > > > 'netstat - -lntu' shows you the TCP or UDP listening sockets. If you are > > > root (or sudo, of course), the extra option -p tells you which process is > > > "at the other side" listening. > > > > > > Note that the dhcp client itself (which you need to get an IP address to > > > take part in your customer's network) puts you already at some risk, > > > depending on how it's configured. > > > > Here is the output from the laptop: > > > > # netstat -lntup > > Active Internet connections (only servers) > > Prot Rec Snd Local Address Foreign State PID/Program name > > -Q -Q Address > > tcp 0 0 0.0.0.0:9999 0.0.0.0:* LIS 561/inetd > > tcp 0 0 0.0.0.0:111 0.0.0.0:* LIS 530/rpcbind > > tcp 0 0 0.0.0.0:46225 0.0.0.0:* LIS 540/rpc.statd > > tcp 0 0 0.0.0.0:22 0.0.0.0:* LIS 568/sshd > > tcp 0 0 127.0.0.1:631 0.0.0.0:* LIS 1248/cupsd > > tcp 0 0 127.0.0.1:5432 0.0.0.0:* LIS 675/postgres > > tcp 0 0 127.0.0.1:25 0.0.0.0:* LIS 1063/exim4 > > tcp 0 0 127.0.0.1:2628 0.0.0.0:* LIS 599/0 > > tcp6 0 0 :::111 :::* LIS 530/rpcbind > > tcp6 0 0 :::38930 :::* LIS 540/rpc.statd > > tcp6 0 0 :::22 :::* LIS 568/sshd > > tcp6 0 0 ::1:631 :::* LIS 1248/cupsd > > tcp6 0 0 ::1:5432 :::* LIS 675/postgres > > tcp6 0 0 ::1:25 :::* LIS 1063/exim4 > > udp 0 0 0.0.0.0:36358 0.0.0.0:* 612/avahi-daemon:r > > udp 0 0 0.0.0.0:631 0.0.0.0:* 647/cups-browsed > > udp 0 0 0.0.0.0:689 0.0.0.0:* 530/rpcbind > > udp 0 0 127.0.0.1:716 0.0.0.0:* 540/rpc.statd > > udp 0 0 0.0.0.0:57106 0.0.0.0:* 540/rpc.statd > > udp 0 0 0.0.0.0:111 0.0.0.0:* 530/rpcbind > > udp 0 0 192.168.1.99:123 0.0.0.0:* 664/ntpd > > udp 0 0 127.0.0.1:123 0.0.0.0:* 664/ntpd > > udp 0 0 0.0.0.0:123 0.0.0.0:* 664/ntpd > > udp 0 0 0.0.0.0:5353 0.0.0.0:* 612/avahi-daemon:r > > udp6 0 0 :::689 :::* 530/rpcbind > > udp6 0 0 :::43913 :::* 540/rpc.statd > > udp6 0 0 :::111 :::* 530/rpcbind > > udp6 0 0 fe80::ba70:f4ff:fe2:123 :::* 664/ntpd > > udp6 0 0 ::1:123 :::* 664/ntpd > > udp6 0 0 :::123 :::* 664/ntpd > > udp6 0 0 :::5353 :::* 612/avahi-daemon:r > > udp6 0 0 :::44274 :::* 612/avahi-daemon:r > > # > > > > Regrettably, the formatting of the output does not consider the need to > > include the output in the body of an e-mail, so editing was required to > > remove excess spaces so as to prevent every line from being wrapped. > > > Something like this should save you from the most troubles provided > that you don't plan to use your laptop as a print server or NFS: > > iptables -P INPUT DROP > iptables -A INPUT -i lo -j ACCEPT > iptables -A INPUT -p icmp -j ACCEPT > iptables -A INPUT -m conntrack --ctstate INVALID -j DROP > iptables -A INPUT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED \ > -j ACCEPT > iptables -A INPUT -p udp -m conntrack --ctstate RELATED,ESTABLISHED \ > -j ACCEPT > iptables -A INPUT -p tcp --dport 22 -j ACCEPT > iptables -A INPUT -p udp --dport 123 -j ACCEPT > > iptables -P FORWARD DROP > > ip6tables -P INPUT DROP > ip6tables -A INPUT -p ipv6-icmp -j ACCEPT > ip6tables -A INPUT -m conntrack --ctstate INVALID -j DROP > ip6tables -A INPUT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED \ > -j ACCEPT > ip6tables -A INPUT -p udp -m conntrack --ctstate RELATED,ESTABLISHED \ > -j ACCEPT > ip6tables -A INPUT -p tcp --dport 22 -j ACCEPT > ip6tables -A INPUT -p udp --dport 123 -j ACCEPT > > ip6tables -P FORWARD DROP > > > Of course, it's *very* simplistic set of rules (for example, someone > may consider accepting ssh connections from arbitrary hosts a bad idea), > but it should work. Why does he need any iptables rules? I see nothing at risk there. It seems to me he can be confident his computer is safe. > Two things I'm unsure of are: > > 1) Avahi's udp 5353. I don't see any value in mDNS (especially in office > network), but YMMV. There is much value in mDNS in an office network with CUPS nowadays. > 2) Whatever thing you're listening for on tcp 9999 with inetd. Ditto.
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laptop protection in an office network rlharris@oplink.net - 2015-08-29 07:00 +0200
Re: laptop protection in an office network Riley Baird <BM-2cVqnDuYbAU5do2DfJTrN7ZbAJ246S4XiX@bitmessage.ch> - 2015-08-29 08:00 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 08:20 +0200
Re: laptop protection in an office network Joe <joe@jretrading.com> - 2015-08-29 09:20 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 10:20 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-29 14:00 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 18:20 +0200
Re: laptop protection in an office network Joe <joe@jretrading.com> - 2015-08-29 18:30 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 20:30 +0200
Re: laptop protection in an office network Reco <recoverym4n@gmail.com> - 2015-08-29 20:40 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 21:10 +0200
Re: laptop protection in an office network Reco <recoverym4n@gmail.com> - 2015-08-29 21:30 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 21:50 +0200
Re: laptop protection in an office network Gene Heskett <gheskett@wdtv.com> - 2015-08-30 02:40 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-30 03:30 +0200
Re: laptop protection in an office network Gene Heskett <gheskett@wdtv.com> - 2015-08-30 03:40 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-30 04:30 +0200
Re: laptop protection in an office network Doug <dmcgarrett@optonline.net> - 2015-08-30 04:50 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-30 05:00 +0200
Re: laptop protection in an office network Lisi Reisz <lisi.reisz@gmail.com> - 2015-08-31 00:20 +0200
Re: laptop protection in an office network Gene Heskett <gheskett@wdtv.com> - 2015-08-30 05:10 +0200
Re: laptop protection in an office network David Wright <deblis@lionunicorn.co.uk> - 2015-08-30 06:40 +0200
Re: laptop protection in an office network Gene Heskett <gheskett@wdtv.com> - 2015-08-30 07:30 +0200
Re: laptop protection in an office network Martin Read <zen75502@zen.co.uk> - 2015-08-31 03:50 +0200
quality keyboards rlharris@oplink.net - 2015-08-31 09:10 +0200
Re: quality keyboards Petter Adsen <petter@synth.no> - 2015-08-31 09:40 +0200
Re: quality keyboards "Gian Uberto Lauri" <saint@eng.it> - 2015-08-31 09:50 +0200
Re: quality keyboards Petter Adsen <petter@synth.no> - 2015-08-31 12:00 +0200
Re: quality keyboards Joel Rees <joel.rees@gmail.com> - 2015-08-31 13:20 +0200
Re: quality keyboards Petter Adsen <petter@synth.no> - 2015-08-31 14:30 +0200
Re: quality keyboards "Gian Uberto Lauri" <saint@eng.it> - 2015-08-31 14:40 +0200
Re: quality keyboards Joel Rees <joel.rees@gmail.com> - 2015-08-31 15:50 +0200
Re: quality keyboards Petter Adsen <petter@synth.no> - 2015-08-31 16:40 +0200
Re: quality keyboards "Gian Uberto Lauri" <saint@eng.it> - 2015-08-31 17:00 +0200
Re: quality keyboards Anthony Maples <anthonym7009@gmail.com> - 2015-09-01 00:10 +0200
Re: quality keyboards "Thomas Schmitt" <scdbackup@gmx.net> - 2015-08-31 16:10 +0200
Re: quality keyboards Haines Brown <haines@histomat.net> - 2015-08-31 13:00 +0200
Re: quality keyboards Curt <curty@free.fr> - 2015-08-31 14:20 +0200
Re: quality keyboards Joel Rees <joel.rees@gmail.com> - 2015-08-31 13:10 +0200
Re: quality keyboards Gene Heskett <gheskett@wdtv.com> - 2015-08-31 14:30 +0200
Re: quality keyboards Petter Adsen <petter@synth.no> - 2015-08-31 15:00 +0200
Re: quality keyboards "Gian Uberto Lauri" <saint@eng.it> - 2015-08-31 15:10 +0200
Re: quality keyboards Lisi Reisz <lisi.reisz@gmail.com> - 2015-08-31 15:10 +0200
Re: quality keyboards Martin Read <zen75502@zen.co.uk> - 2015-08-31 13:20 +0200
Re: quality keyboards David Wright <deblis@lionunicorn.co.uk> - 2015-08-31 17:40 +0200
Re: quality keyboards Glenn English <ghe@slsware.net> - 2015-08-31 18:30 +0200
Re: quality keyboards Don Armstrong <don@debian.org> - 2015-08-31 21:50 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-29 21:10 +0200
Re: laptop protection in an office network Reco <recoverym4n@gmail.com> - 2015-08-29 21:20 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-29 21:50 +0200
Re: laptop protection in an office network Reco <recoverym4n@gmail.com> - 2015-08-29 22:00 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 00:10 +0200
Re: laptop protection in an office network Reco <recoverym4n@gmail.com> - 2015-08-30 00:30 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 00:50 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-30 09:40 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 16:10 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-30 18:30 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 20:50 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 21:30 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-29 22:00 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 22:30 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-29 22:50 +0200
Re: laptop protection in an office network Renaud (Ron) OLGIATI <renaud@olgiati-in-paraguay.org> - 2015-08-29 23:40 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-29 23:00 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 00:30 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-30 09:50 +0200
Re: laptop protection in an office network Joe <joe@jretrading.com> - 2015-08-30 10:30 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-30 10:40 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-30 01:50 +0200
Re: laptop protection in an office network Chris Bannister <cbannister@slingshot.co.nz> - 2015-08-30 09:30 +0200
Re: laptop protection in an office network <tomas@tuxteam.de> - 2015-08-30 10:30 +0200
Re: laptop protection in an office network rlharris@oplink.net - 2015-08-30 11:10 +0200
Re: laptop protection in an office network Brian <ad44@cityscape.co.uk> - 2015-08-30 21:10 +0200
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