Concerned with software or hardware firewalls

learn more… | top users | synonyms (1)

2
votes
6answers
610 views

How do I prevent data from leaving my network?

I have a network of about 10 computers and I want to prevent sensitive data and source code leaks. To achieve that, I would like to block all file uploading / attaching. What are the options ...
2
votes
2answers
359 views

How does a firewall help to protect a server?

Since a potential attacker will exploit the services that are already open to public by firewall rules, how will a firewall help to protect my server from attackers?
2
votes
3answers
5k views

What, specifically, does the Windows Firewall do?

My understanding of the situation is that, when the Windows firewall is off, every port on the computer (all 65535 of them) is fully open. This means that any application running on the computer can ...
2
votes
3answers
1k views

How to block the websites on client machines

In our office we are blocking sites like Facebook, Twitter etc.The problem is that some of the users bypass our proxy and firewalls through external proxy sites like www.youhide.com or ...
2
votes
4answers
1k views

Best way to push data to a client without being blocked by firewall

I'm asking this question here since I think people on this forum probably have the best knowledge of firewalls and routers. Say I'm designing a multi-player game and I want to push data to the client ...
2
votes
2answers
252 views

Identify if files are being transferred from my computer over the internet

This may seem like a silly question to most, but... I recently has some spyware infected on my machine, which I have since gotten rid of. Using a couple of scanners (that come recommended on various ...
2
votes
2answers
196 views

Access via http to other protocols and ports!

Our firewall only allows HTTP port 80 but we have detected that a user accesses some other protocols and ports that we deny in our firewall. We know that he has developed an application (Console ...
2
votes
2answers
272 views

Web Application Firewall Rules

For Network Layer Firewalls we have different sort of redundancy and consistency checks like rule shadowing, that can impact the performance of firewall. Do similar kind of checks can be applied on ...
2
votes
2answers
323 views

Firewall & TCP Traffic

I have a question regarding network firewalls and TCP traffic. When a firewall rule is set to block either inbound traffic, outbound traffic, or both on a port, does that only apply to initial ...
2
votes
3answers
462 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 ...
2
votes
5answers
2k views

SYN flooding attack causing high CPU on hardware firewall

I have a ZyWall USG 200 firewall. A few days ago there was a SYN flooding attack on it causing 100% CPU load. After investigating it turns out this was attack from a single IP address and while the ...
2
votes
3answers
908 views

Reviewing IP(s) that has been blocked by firewall / router

Is there a best practice on how to review IP(s) that are blocked on firewall / router and determine if they are safe to be removed from banned list? Occasionally, the firewall guys see a high counts ...
2
votes
1answer
279 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 ...
2
votes
2answers
242 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 ...
2
votes
2answers
3k views

IPTables DDoS protection working with per client IP address counter AND UDP

I am looking to protect LAMP server with a software, which will detect above average number of requests from single IP numbers (in this case DNS queries), and add these hosts to IPTables deny chain. ...
2
votes
2answers
1k views

Why is my firewall blocking on some files but not others?

I'm behind a corporate firewall which restricts access to certain urls and most downloads. The download restriction is mainly on .exe(but it allows some exe files to be downloaded and I don't know ...
2
votes
2answers
416 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
2
votes
3answers
497 views

Why block network ports?

There was another good question here on why you should block outgoing traffic: Why block outgoing network traffic with a firewall? But I was hoping to get an answer on why it is a good idea to block ...
2
votes
2answers
647 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 ...
2
votes
3answers
3k views

Is it really better to use port 80 or 443 for outgoing traffic in order to bypass user firewall?

I recently created a reverse connection shell in C#. I tested it with some computers and I noticed that some computers connected back correctly and I established connection with them but another ...
2
votes
1answer
823 views

Incoming Packet From Source Port 80

I'm sure no daemon or browser is using network resources, but I found incoming packets from Wireshark: 98.126.43.174 source port 80 --TCP--> MyIp destination port 339 [SYN, ACK] 98.126.43.174 ...
2
votes
1answer
187 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 ...
2
votes
2answers
335 views

Enterprise IDS - Deployment & Uses

I am investigating deploying the Snort IDS for an enterprise environment. This environment consists of a NOC that manages several servers, mainly internal but some internet facing. There are several ...
2
votes
2answers
363 views

Why wouldn't the reverse shell connect back using the same port that exploited the server?

The reverse shell payload from msf use a new port to connect back to the attacker, therefore if the target server has outgoing filters, attack would fail. i.e established server:ftp <-> ...
2
votes
3answers
813 views

Firewall Migration: NetScreen NS500 to FortiGate [closed]

I have recently been tasked with doing a firewall migration from an old NetScreen NS500 box to a FortiGate device (I believe it will be a 60C). I am sure most of you aware that NetScreen boxes are no ...
2
votes
1answer
31 views

Virtualisation: security on the host side

Virtualised environments are focused on isolating the guest OS. Using the VirtualBox model, the guest might be behind a virtual NAT and/or talk only with other VMs via internal networks, and only ...
2
votes
3answers
313 views

Suspicious VMWare connections that bypass firewall

I'm running VMWare 5 and I have found that when I start up VMWare I see two connections: TCP 10.100.100.161:55555->as-40816.engx.vmware.com:https (ESTABLISHED) TCP ...
2
votes
1answer
223 views

How are IaaS Virtual Machines Isolated?

I am currently examining Hypervisor firewalls for my graduate thesis, but I unfortunately don't have a lot of experience with IaaS environments. How are IaaS Virtual Machines network isolated from ...
2
votes
1answer
565 views

Why are some ports reported as closed by nmap?

I was scanning a machine from inside the same LAN which is running and up to date Windows XP Home Edition which I suspect may be running some malware. The target machine has an up to date antivirus ...
2
votes
2answers
2k views

What is more risky? Database Server in DMZ or Trusted Network?

Hoping this is not a dupe of any of the related database / DMZ questions, but I don't think any of them answered my question sufficiently. Assume the following A web server is being used for ...
2
votes
3answers
1k views

Effectively limiting outgoing firewall traffic to frequently-changing IPs

PCI DSS 1.2.1 states: Restrict inbound and outbound traffic to that which is necessary for the cardholder data environment. Verify that all other inbound and outbound traffic is ...
2
votes
3answers
7k views

Config Server Firewall: What Outgoing ports need to be open for wget and apt-get install?

I am just configuring CSF and I have to specify my outbound ports here. I am trying to close as many as possible leaving only what I need open, however what do I need to leave open for wget? # Allow ...
2
votes
2answers
236 views

Project help required by a newbie!

Basically, I'm doing a degree in network computing and am currently working on my dissertation right now. I am not an expert with networking yet, so I'm kind of struggling to get started with my topic ...
2
votes
3answers
1k views

Recommendations for security gateway/firewall management tools (Juniper SRX) [closed]

I am seeking recommendations for management tools for high-end firewalls, such as the Juniper SRX3000 series. When I say "management", I mean operations, configuration management, policy management, ...
2
votes
1answer
116 views

Docker port forwarding exposure

I try docker with a simple webapp : docker run -d -v $(pwd):/app -p 8080:80 image_name I have docker listen on 8080: tcp6 0 0 :::8080 :::* LISTEN ...
2
votes
1answer
689 views

Expose web service in a secure manner

Requirement I have a web service I need to expose on the DMZ for external communication. The web service communicates directly with a critical database that sits on an internal net. Current ...
2
votes
3answers
146 views

State before getting whitelisted?

There is a data flow of incoming files (from untrusted, external sources), that get whitelisted by a kind of application layer firewall. Is there a common name for the state of the files before they ...
2
votes
1answer
198 views

What security risks are involved with sending data over the internal network on Rackspace Cloud servers?

What are the risks involved with sending unencrypted data over the internal network with Rackspace Cloud Servers? Assume the interfaces use iptables to filter IPs and ports so they only accept data ...
2
votes
1answer
7k views

How does pfsense block torrent traffic?

I know that pfsense is a very effective tool for restricting bit torrent traffic. I was wondering how it actually manages to do that ? There's not much information available on this. The more ...
2
votes
2answers
416 views

Anomaly based web application Firewall

How practical are anomaly based web application firewall in mitigating web based attacks ? Which types of threats do they mitigate against and which don't they? Are their any practical implementation ...
2
votes
1answer
44 views

Should reverse connections be used to bypass NATs?

I'm planning on doing a demonstration on how remote administrative tools work for my schools computer security club. I plan on writing a RAT in C++ and demonstrating/explaining how it works. I ran ...
2
votes
1answer
469 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: ...
2
votes
1answer
258 views

IPS/IDS and Firewall Solution(s) to a Small Office

I was tasked with implementing a network security solution for a small real estate agency. They are a typical old-school mom and pops shop, about 15 employees with basic file sharing, printing, and ...
2
votes
1answer
87 views

Windows: Any method to enforce user confirmation before the browser opens a URL requested by an external desktop app?

A robust outgoing firewall will protect against desktop applications directly connecting to the internet without your permission. However, as the browser is a generally authorized application for ...
2
votes
2answers
490 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 ...
2
votes
2answers
251 views

Barracuda antispam access to active directory in dmz : opening port or not?

I have a Barracuda Antispam unit and look to use recipient validation with active directory to stop sending NDRs (non-delivery reports) when we are being spammed. What I see on the web is people ...
2
votes
1answer
242 views

Normalizing Windows Advanced Firewall rules

How can I best normalize our Windows Advanced Firewall rules while implementing network segmentation? I want them to be as clear and concise as possible for audit purposes. What few examples I've seen ...
2
votes
1answer
95 views

Quick Security Mitigations to Impending attacks

Suppose you are the sysadmin, and you know of an impending attack that just started or about to start soon. You can either wait it out, or try a few tricks and quick mitigation to fend off attackers ...
2
votes
2answers
326 views

How to define different firewall rules for different users on the same machine running on Windows 7?

Provided that one machine running on Windows 7, connected to LAN, and connected to the Internet via a gateway in the LAN. There are two logon user accounts A and B on the machine. I want: 1, User A ...
2
votes
2answers
436 views

Does an equivalent for netconf exist in the Cisco ASA world?

I'm looking for a method to send instructions to a Cisco ASA without writing scripts to execute on the CLI over SSH. Cisco doesn't seem to support netconf or xml-pi on the physical ASAs (only their ...