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Questions tagged [iptables]

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An application that allows a user to configure the tables provided by the Linux firewall. iptables is succeeded by nftables as of 2014.

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Reject IP packets with an ICMP error, or just drop them?

Consider an internet-facing host (the outer firewall). What should be done with undesired traffic: just drop it, or send back an ICMP error such as port unreachable? (In Linux terms: iptables -P DROP ...
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1answer
1k views

How to prevent outgoing UDP attacks?

My server has been the target from hackers 3 times in the last month, and the attack seem to follow the same pattern. The attack another site from my server using UDP connection. The report from my ...
2
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2answers
1k views

Dealing with the dangers of self-hosting a webserver?

Assuming for a self-hosted webserver: the webserver only hosts a static html website iptables is used to reject every IP except a few known ones only Port 443 is forwarded and the website requires ...
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4answers
1k views

Find out what Linux software is trying to phone home

I have seen some suspicious outbound communications blocked on my VPS, which hosts a small experimental Web site, and want to find out which application is making the attempt. The server is running ...
2
votes
2answers
663 views

Isolating guest networks

I'm setting up a secondary guest wifi on my router and I want to make sure that it's impossible for clients connected to the guest wifi to access my primary network. Initially, I used IP filtering ...
3
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2answers
6k views

How to configure iptables for must open ports?

On my machine there are web services which can be accessed from any PC connected to the same network segment (WiFi for example). I want to use IPtables on the machine to prevent any web services from ...
3
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1answer
2k views

Setting up a fake AP - problem with iptables and DNS server

Im trying to set up a fake AP using aircrack-ng suite, DHCP server & iptables. After creating the fake AP: airmon-ng start wlan1 airbase-ng -c 11 -e "freewifi" wlan1mon running iptables ...
3
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2answers
1k views

Firewall egress filtering / quick whitelisting

Suppose your Aunt or Uncle is easily fooled by phishing attempts and their computer has multiple root kits and key loggers running. Assume their computing habits will never change. Looking at his ...
2
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1answer
2k views

MitM-Position with bridged network and iptables

I'm currently trying to get my setup to work. [ victim ] --- [ mitm ] --- [ net ] IPs: net: 10.0.0.0/24 victim: 10.0.0.1 mitm: 10.0.0.2 gateway: 10.0.0.254 setup: ip l a name br0 type bridge ip l ...
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0answers
33 views

What is the most restrictive way to allow IPv6 ICMP requests on iptables?

This is what I have so far but it is pretty open. *filter :INPUT DROP [0:0] :FORWARD DROP [0:0] :OUTPUT DROP [0:0] -A INPUT -p ipv6-icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A OUTPUT -p ipv6-icmp -j ...