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On Fri, Apr 24, 2009 at 4:59 PM, Eric Martin <freak4uxxx@×××××.com> wrote: |
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> Marco wrote: |
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>> Hi all, |
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>> |
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>> I set up my first firewall on my notebook (not running any services |
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>> reachable from outside) using iptables. Since I am new to the topic, |
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>> could you please verify if the output of 'iptables -L -v' is |
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>> considered to be a safe firewall? Thanks! |
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>> |
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>> Chain INPUT (policy DROP 0 packets, 0 bytes) |
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>> pkts bytes target prot opt in out source |
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>> destination |
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>> 0 0 ACCEPT all -- lo any anywhere |
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>> anywhere |
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>> 0 0 ACCEPT all -- eth0 any anywhere |
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>> anywhere state RELATED,ESTABLISHED |
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>> 0 0 REJECT tcp -- eth0 any anywhere |
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>> anywhere reject-with tcp-reset |
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>> 0 0 REJECT udp -- eth0 any anywhere |
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>> anywhere reject-with icmp-port-unreachable |
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>> 0 0 DROP udp -- eth0 any anywhere |
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>> anywhere udp spt:bootps |
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>> 0 0 LOG all -- eth0 any anywhere |
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>> anywhere LOG level warning prefix `INPUT ' |
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>> 1 79 ACCEPT all -- wlan0 any anywhere |
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>> anywhere state RELATED,ESTABLISHED |
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>> 0 0 REJECT tcp -- wlan0 any anywhere |
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>> anywhere reject-with tcp-reset |
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>> 0 0 REJECT udp -- wlan0 any anywhere |
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>> anywhere reject-with icmp-port-unreachable |
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>> 0 0 DROP udp -- wlan0 any anywhere |
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>> anywhere udp spt:bootps |
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>> 0 0 LOG all -- wlan0 any anywhere |
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>> anywhere LOG level warning prefix `INPUT ' |
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>> |
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>> Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) |
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>> pkts bytes target prot opt in out source |
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>> destination |
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>> 0 0 LOG all -- any any anywhere |
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>> anywhere LOG level warning prefix `FORWARD ' |
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>> 0 0 LOG all -- any any anywhere |
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>> anywhere LOG level warning prefix `FORWARD ' |
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>> |
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>> Chain OUTPUT (policy ACCEPT 5 packets, 1691 bytes) |
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>> pkts bytes target prot opt in out source |
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>> destination |
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>> 0 0 ACCEPT all -- any lo anywhere |
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>> anywhere |
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>> 0 0 LOG all -- any eth0 anywhere |
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>> anywhere LOG level warning prefix `OUTPUT ' |
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>> 1 52 LOG all -- any wlan0 anywhere |
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>> anywhere LOG level warning prefix `OUTPUT ' |
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>> |
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>> |
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> It all depends on what you're trying to do. My internet facing boxes |
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> have a default OUTPUT policy of DROP and I only allow certain traffic |
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> off of the box (helps protect me from unauthorized services). Also, |
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> you're dropping bootps (same ports as dhcp) on udp so I don't think you |
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> can get a dhcp address like that. If you're running any services you |
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> won't be able to talk to them (ssh). Turn off forwarding in the kernel |
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> config (via /etc/sysctl.conf) as well. |
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I am dropping bootps to not have my log file flooding due to the DHCP |
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server in my wireless router (as suggested in |
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www.novell.com/coolsolutions/feature/18139.html). As it seems I still |
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get a dynamic ip from it. |
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So far, I am not running any services that have to be exposed to the outside. |
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> It also took me a few runs to figure out the firewall config (due to the |
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> rules and formatting). The last two output rules can be combined into |
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> one. Have 1 log line at the bottom of your tables and that will take |
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> care of that. Clean and short configs will help immensely when things |
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> don't work. |
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Sorry for the bad format. gmail decided to insert some sub ideal pagebreaks... |
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Talking about the 1 log line at the bottom you mean I should configure |
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it to not specify an interface (eth0, wlan0)? |
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Thanks! |
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