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2
votes
2answers
7k views

Test firewall rules (Linux)

I have a question about how to test the firewall rules. To be more specific, for academic purpose I have to set up a machine which will accept all kind of packets o a specific interface. I added an ...
2
votes
2answers
5k 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 ...
0
votes
1answer
2k views

icmp packets not able to reach the firewall despite of adding a specific rule, why?

I am using iptables to allow the icmp traffic in/out of my host. Please find below are the entries from my firewall (linux based):- [root@localhost ~]# iptables -L Chain INPUT (policy DROP) target ...
0
votes
3answers
432 views

Some issues with iptables and nmap

When I scan my pc with nmap I see only one open port. I didn't define any rule in iptables so if I'm not mistaken, all connections should be denied by default. However I can use HTTP or SSH, so that ...
2
votes
1answer
192 views

Consequences of using -s and -d arguments in iptables

We are studying iptables for a Computer Systems Security course. We are confused as to what happens when the -s and -d arguments are both used in the same rule, such as: iptables -A OUTPUT -s ...
1
vote
2answers
812 views

How is iptables useful to prevent attacks against a LAN?

I need some advice securing a LAN using iptables. I've found lots of examples on how to secure single host with iptables, including scanning ports, attacking using ICMP-flood and TCP-flood. These ...
1
vote
1answer
221 views

IPtables - Accept Arbitrary Packets

I've achieved a lot on blocking attacks on GameServers but I'm stuck on something. I've blocked major requests of game-server which it aceepts in the form "\xff\xff\xff\xff" which can be followed by ...
1
vote
4answers
4k views

Ignoring broadcasts to 10.0.0.255 using iptables

I'm trying to drop logging packets that are destined for 10.0.0.255 by using the following rules: $IPTABLES -A OUTPUT -d 10.0.0.255 -j DROP $IPTABLES -A FORWARD -d 10.0.0.255 -j DROP It ...
3
votes
2answers
267 views

Can ipopts be used to circumvent a pf or iptables firewall source IP based blocking?

Can one use ipopts, and in particular IP source routing, to circumvent source-based blocking in pf or iptables? For example, with OpenBSD's pf: block in all # default deny block out all pass in on ...
7
votes
4answers
22k views

Tips for a secure iptables config to defend from attacks. (client side!)

Own examples: ############### # KERNEL PARAMETER CONFIGURATION # PREVENT YOU SYSTEM FROM ANSWERING ICMP ECHO REQUESTS echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all # DROP ICMP ECHO-REQUEST ...
1
vote
2answers
3k views

IPTables default security rules for a gateway/router?

On a router such as dd-wrt or tomato, what would be some default iptables rules? I am asking for rules on a router/gateway - For example; blocking SYN flood attacks, or XMAS attacks. The basic ...
4
votes
4answers
2k views

what is a good public available iptables script for ddos mitigation?

what is a good public available iptables script for ddos mitigation?
6
votes
5answers
999 views

Firewall demo - iptables

I have to make a demonstration about firewalls in my class as a student(university). It should be implemented using iptables on Linux. I am reading all the theories around them but I can't figure out ...
13
votes
2answers
4k views

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 ...