Concerned with software or hardware firewalls

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internal proxy server vs DMZ proxy server

What would be reason for placing a proxy server in a Demilitarized Zone (DMZ)? I understand that a DMZ is a separate network to your internal network (lies inbetween internal network and firewall). I ...
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1answer
25 views

NAT separate firewall or other security tools

It's a conceptual question: Suppose i want to separate NAT and firewall, can it help to my security? INTERNET >>>> NAT >>>> Firewall >>> MyNetwork
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2answers
84 views

How do proxy servers protect their SSL certificates?

Suppose that there is a http proxy server outside the firewall of an organization hosting a web server. All client connections to the web server happen through this proxy. The client negotiates SSL ...
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5answers
66 views

Firewall rules by URL

is there a solution to create FW rules by URL instead of IP for inbound traffic? For example a.example.com and b.example.com are the same IP on the DNS, but they are different sites, is there a ...
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2answers
77 views

Is it not safe to open MySQL's port to the internet?

The consensus on this Server Fault question seems to be that opening port 3306 for MySQL is more dangerous than using an SSH tunnel to access MySQL. I would think that with strong credentials you ...
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0answers
68 views

iptables raw table

I'm trying to collect iptables common shield rules, here is my current list: echo "-Check for All flags enabled&Drop." iptables -I INPUT -p tcp --tcp-flags ALL ALL -j DROP echo ...
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2answers
84 views

How does Network Address Translation (NAT) increase firewall effectiveness

Truth or bald-faced lie: the cheap $50 router you can pick up at your local electronics store for your home broadband Internet connection is actually a pretty effective firewall. Why or why not? How ...
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0answers
20 views

How to use the Suricata IDS to monitor the entire network? [migrated]

I have the following 3 PCs connected to a router via Ethernet: PC1 – 192.168.1.101 (Linux Ubuntu) PC2 – 192.168.1.100 (Windows) PC3 – 192.168.1.1 (Windows) All PCs can ping each other. PC1 has ...
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1answer
161 views

Is it safe to disable connection tracking in iptables?

While reading about NOTRACK target of raw table in iptables, I encountered an article suggesting that for certain traffic you could (or even should) disable connection tracking. The two examples were: ...
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1answer
96 views

Is a firewall an access control list?

I want to know if a firewall is considered an access control list (ACL). I know there are other types of ACLs, but am specifically interested in knowing if a firewall is an ACL. Edit: It appears ...
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2answers
170 views

How to block network scans with pfsense?

I am using pfsense as firewall, and I would like to know how I can stop network scans from enumerating open services and ports. Thanks
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1answer
75 views

DMZ Firewall settings

I am involved in project where I have to install a new server for a new application to a preexisting production network. The new server shall sit in the DMZ and two controllers will sit on the ...
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2answers
112 views

Securing a Windows PC

Currently I have an "Antivirus" and Anti Malware software installed. In addition I closed all remote assistance and unused port rules on my firewall. I'd really like to get a complete as possible ...
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0answers
24 views

Is it possible to covertly tunnel data using L3DSR? (or any other TCP or IP layer hack)

I asked this question on ServerFault regarding how a Netscaler embeds low level data in a TCP packet, round-trips it, and then uses that data to loadbalance the user. Similar to DNS Tunneling, I ...
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5answers
6k views

Are two firewalls better than one?

Let's say that our first firewall have some vulnerability and malicious person is able to exploit it. If there's second firewall after it, she should be able to stop the attack, right? Also what will ...
0
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1answer
34 views

ESET detected incoming connection to Rundll32

My ESET Smart Security 7 detected incoming connection from an external computer, since Rundll32 can be run by any programs on my computer and I don't know which program is doing this, so I am ...
0
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1answer
102 views

Firewall hole punching [closed]

I'm interested in doing my thesis on Firewall hole punching. Hole Punching: A way to exploit NAT to open a connection TCP or UDP between a Client and a Server. What I'm looking for is a reason this ...
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2answers
146 views

Do I need a hardware firewall even if I have Internet security software?

I have Kaspersky Internet Security 2010 installed on my Win7 computer. I assume it gives me enough protection for a software firewall(port security,tracking tcp,udp traffic etc.) Do I still need a ...
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2answers
252 views

VPN blocked ports problem

I use VPN quite often in public places where I don't want anyone to read my web traffic. However, some public places have firewalls that block ports required to establish a VPN connection (I usually ...
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2answers
140 views

How to prevent attacks to server

I have 3 CentOS server configured for my applications. Recently I recognized that there is so many attacks to my servers. I have so many logs about attempt to login to my servers using sshd from ...
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2answers
55 views

Intrusion detection system and firewalling

I have a website and hosted some data and MySQL files on it. Is it possible for me to install an intrusion detection system on it, or can IDSs only be installed on my internal network where I have a ...
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5answers
127 views

Do firewalls always run in userspace?

There are many Firewall solutions for the world on different operating systems: iptables, pf, ipfw. My question is: Does the firewalls run in kernel-space or all of them runs in user-space? (in ...
2
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1answer
240 views

How can the Google web crawler bypass portals?

This is a situation that I have encountered on a number of occasions. I will conduct a web search in Google, a link to a file (.pdf for example) will take you to that file on the server. It opens up ...
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0answers
62 views

How should I configure my Tor-dedicated firewall for optimum security?

I'm setting up a Tor-based isolating proxy using the 'Anonymizing Middlebox' iptables rules specified here: https://trac.torproject.org/projects/tor/wiki/doc/TransparentProxy i.e. iptables -t nat ...
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0answers
28 views

Carry out an attack on port 80 while only 20 is allowed [duplicate]

There is a question bugging me a after reading on network security. Theoretical situation: there is a packet-filtering firewal which only accepts tcp / ip communication with destination port 22 on a ...
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1answer
53 views

If I port scan a server on the outside of a firewall will this also tell me the ports the firewall is blocking?

Theoretically I was thinking a firewall inspects the TCP header and looks at the destination port and discards/forwards based on its firewall rules. So could I port scan an external server to the ...
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0answers
76 views

OpenVPN and firewall configuration in LuCI

I'm trying to find the best (most secure) configuration for the firewall in OpenWRT. I'm using LuCi to configure all the stuff. I have successfully created a VPN (OpenVPN). It is supposed the best ...
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1answer
143 views

Foreign MRT.exe?

I was managing my firewall using AVG and I noticed this was allowed: I have north american locale, and sometimes Japanese locality(?), and that is not Japanese. It is getting through my firewall, ...
0
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1answer
478 views

how to bypass windows xp firewall with nmap

I'm scanning a Windows XP in a virtualized environment. I use all of needed arguments to bypass its firewall but it doesn't answer: nmap -e eth0 -Pn --data-length 5 --badsum -g 80 -S 192.168.1.103 -f ...
2
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1answer
105 views

ASA5505 DMZ issue

I have ASA5505 , connected to the WAN on port 0 (called Vlan2), and connected to my development LAN on port 7 (Called Vlan1). I want to add DMZ, and I connected switch and servers to port 3, and ...
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2answers
47 views

Does it make sense to log accepted traffic on firewall?

Assuming a firewall is properly setup, only allowing determined traffic and dropping everything else, what relevant information (if any) could I get from the log of the accepted rules? From the ...
0
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1answer
121 views

Finding the firewall port that filters internet traffic [closed]

In my office, we have static IP's for each system. All the internet traffic from our systems are filtered with a Fortiguard firewall. Is it the default gateway where the firewall is installed? How can ...
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4answers
97 views

Is it possible to block specific users that connect to the internet behind of same gateway with NAT?

Assume there are two internet users (A and B) that connect to the internet from the same gateway by using NAT. That means they use same IP address while passing through our firewall. Now assume we ...
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1answer
66 views

Allow loopback in Iptables?

I'm trying to write Iptables rules for a small web server. Almost every source I've encountered recommends to allow loopback access to the web server, but doesn't explain why this is necessary. ...
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4answers
195 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 ...
0
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1answer
106 views

Would encryption bypass some firewall rules?

Would an encrypted connection be able to bypass a firewall? A firewall is working on layer 1-4 of OSI model, the encryption and decryption is done in presentation layer (layer 7 of the OSI model). Can ...
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3answers
81 views

How source port field in firewall rule is used

Some firewalls (like the first figure in 13.1.4 in http://doc.m0n0.ch/handbook/examples.html) allow user to specify source port in a firewall rules. But in a TCP connection, the source port is ...
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2answers
147 views

What security does an ISP provide for its customers?

I've heard that ISPs provide some kind of protection; using NAT and firewalls, to prevent hackers from using tools such as nmap to attack customers from over the Internet. What other technologies are ...
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2answers
207 views

Could a router protect our network or need we use an hardware firewall?

I am at a small firm (12 PC on the internal network). We use this network architecture now: Internet(Modem) --> Router --> Firewall --> Switch -- > Internal Network (clients PCs) ...
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1answer
592 views

Windows Firewall netsh equivalent of iptables u32 module

I have looked everywhere and I can't seem to find a netsh equivalent of the u32 module for iptables. I want to create a rule to Drop a packet that starts with a specific set of bytes. Similar to: # ...
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2answers
309 views

Blocking incoming traffic from privileged port (< 1024) to mitigate DNS DDos Amplification attacks

Hope someone can clarify. As I understand, in a DNS DDos Amplification attacks Multiple DNS queries are sent to a vulnerable name server with the source IP spoofed to that of the target server. The ...
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1answer
80 views

Sky Broadband Shield

I was just wondering the implication's to Sky's new revelation of a so called 'shield'. Is this actually even a security feature or just a advertisement stunt for Captain America. I can find very ...
0
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1answer
329 views

Dual Firewall DMZ

We've just learnt about firewalls and DMZ and I'm struggling to understand how are these actually implemented ? The architecture we've learned was something like this: Let's say that we have a ...
4
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3answers
305 views

Can a web server be secured with just a firewall?

I'm about to go online with my first web site, it is a small project hosted on a regular home PC running Windows 7. I want to keep the software footprint at minimum, so it only contains the operating ...
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0answers
32 views

API deployment infrastructure

We are going to deploy our service, it's drupal based with some additional REST APIs. The drupal servers will be (loadbalanced) put in the DMZ. We think to deploy the REST APIs on an app server in ...
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2answers
68 views

Is rolling my own firewall on top of my normal firewall dangerous?

I'm thinking about playing with/learning about firewalls. It is easier for me to learn by building, so why not build a firewall? If I run it alongside my normal firewall, I'd get the normal ...
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4answers
162 views

Comprehensive audit of firewall - is Internet truly not accessible?

We have many Linux servers in several co-locations over the world. By design, these machines generally should not be able to access the Internet. Depending on location and role, some sites may have ...
2
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1answer
225 views

How to configure Suricata to not interfere with virtual machine

I'm currently planning on setting up Suricata as a firewall on my laptop. I'm wondering however if it's possible to set Suricata to not interfere with traffic to and from specific virtual machines ...
0
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1answer
117 views

Is it a bad idea to use port forwarding as a long-term access strategy?

We are deploying multiple copies of the same system (some devices behind a gateway with NAT), and we need to have continued access for some of those devices. Right now our strategy is to have a set of ...
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2answers
181 views

SSH Security allowing only certain users to connect to the server [closed]

I have set up a remote ssh server on the cloud. I am newb at these things and have managed to bypass the required firewall using SSH. Now I plan on giving the access to only 2 more friends of mine so ...