1
vote
0answers
18 views

Should my server ever need to directly communicate with the NAT gateway? [migrated]

What I mean by ``directly communicate'' Does it ever need to receive packets with the gateway's IP address as the source IP address, or send packets with the gateway's IP address as the destination ...
0
votes
3answers
102 views

How to set iptables to drop packets that I'm not listening on?

I've got a Kali Linux box I use for pen testing. I would like to configure my machine to DROP incoming packets, but only when I'm not listening on them. e.g. if I run a netcat listener on port 80, I ...
1
vote
2answers
163 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 ...
0
votes
1answer
466 views

Securing my firewall (both dedicated and iptables-based) [closed]

I have an ASA-5510, but I also intend to maintain strict IP tables on my server (Ubuntu 12.04.2), so that there are two layers of "protection". My iptables look like this: *filter # Allows all ...
0
votes
3answers
389 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 ...
1
vote
3answers
3k 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
263 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 ...
5
votes
4answers
19k 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
1k 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
925 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 ...
12
votes
2answers
3k 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 ...