Tagged Questions
0
votes
1answer
90 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
1answer
242 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
276 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
115 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
366 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
167 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
3answers
1k 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
232 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 ...
4
votes
4answers
10k 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 ...
0
votes
2answers
2k 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
941 views
what is a good public available iptables script for ddos mitigation?
what is a good public available iptables script for ddos mitigation?
4
votes
4answers
677 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 ...
10
votes
2answers
1k 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 ...
