2
votes
1answer
46 views

How To Find Out What 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 am wanting to find out which application is making the attempt. The server is ...
2
votes
3answers
325 views

iptables: plaintext password protection

I'd like to find a way to block or restrict my access to the web-pages where my password is sent as a plaintext on the internet. Let's assume if I have the same password for all web-pages, is it ...
0
votes
1answer
138 views

How does a website get pass my server firewall and attempt to hotlink to my server resources?

I was stumped when I saw the following lines on my Apache server error log this morning: [authz_core:error] [client ::1:37317] AH01630: client denied by server configuration: ...
0
votes
1answer
196 views

Bridge Firewall vs Routing Firewall

What is the difference between bridge and routing firewall ? How they both works and what are the security advantages/disadvantages for both scenario ?
2
votes
2answers
225 views

Are there “LAN IPs” on the internet?

I have a home-made web application and thought that an easy way to secure it's administration interface would be to simply reject all IPs that arent from 192.168... Is this viable? is it possible for ...
1
vote
0answers
137 views

Throttling DropBox behind a firewall

Our office network bandwidth gets choked when an employee copies a large file into her DropBox, since it gets downloaded on several machines (of other employees). LAN Sync is an option, but needs to ...
-1
votes
2answers
139 views

Linux: Blocking outside attempts at attacking computer

in the past when I wanted to block outsiders from attempting to start connections with my Linux machine's various TCP services, what I was told to do was to add this line to /etc/hosts.deny: ...
2
votes
2answers
279 views

Benefits of REJECT over DROP on a single PC

Recently I learned about the difference between DROP and REJECT in a firewall. I understand that REJECT is better because it closes the connection immediately instead of waiting for timeout as DROP ...
1
vote
1answer
189 views

fail2ban and iptables

Should fail2ban be the master of iptables rules? For example, should I setup my firewall rules along side the fail2ban rules, or should I have all my services configured and managed by fail2ban? ...
2
votes
0answers
77 views

Shorewall stopped policies - routeback

Here goes a very specific question about the insides of Shorewall and Iptables in general. Shorewall supports configuration of "Stopped Policies" using the file routestopped, which defines the ...
2
votes
2answers
381 views

Mixing stateless and stateful firewall rules

I have been advised that mixing firewall rules that are both stateful and stateless can lead to trouble when it comes to troubleshooting. Is there any truth in this? Take the following two rule sets ...
1
vote
2answers
132 views

IPTable Security between two servers

Is using IPTables to only allow traffic between two servers considered an acceptable practice? For example TCP traffic on a defined port. I realize this is referred to as an ACL but how secure is ...
0
votes
1answer
295 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
1k 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
353 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
166 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
616 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
201 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
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
255 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
17k 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
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
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
877 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 ...