Concerned with software or hardware firewalls

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226 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
188 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
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2answers
267 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 ...
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2answers
275 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
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3answers
403 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 ...
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5answers
1k 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
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3answers
838 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
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2answers
239 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 ...
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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. ...
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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
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1answer
226 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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3answers
417 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 ...
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2answers
502 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 ...
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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
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1answer
717 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
180 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 ...
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2answers
321 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 ...
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2answers
345 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 <-> ...
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3answers
736 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
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3answers
289 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
210 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
497 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 ...
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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
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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 ...
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3answers
6k 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 ...
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2answers
233 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 ...
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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
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1answer
536 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
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1answer
472 views

Isolate a Virtualbox VM from local network [closed]

I have the need to isolate a virtual machine created with Virtualbox from the local network but I need to provide internet access to that machine. It is the first time that I face this kind of ...
2
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2answers
2k views

What's the difference between an application-level and circuit-level gateway?

From Wikipedia, I understand that circuit level gateways look at TCP handshakes to filter illegitimate traffic and that application level gateways somehow filter application specific traffic. But I ...
2
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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
188 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
6k 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 ...
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2answers
404 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 ...
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1answer
177 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
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2answers
447 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
240 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
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1answer
231 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
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1answer
94 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
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2answers
287 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
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2answers
415 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 ...
2
votes
1answer
4k views

How to block all access to Akami deploy servers and Apple push servers?

I no longer blindly trust the numerous connections that occur at night and during the day that always go to "content" and "push" servers like: a23-33-37-54.deploy.akamaitechnologies.com ...
2
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1answer
207 views

IDS/WAF scenario for 2 web servers

I'm running 2 web servers on 2 different physical hosts at home. They handle both HTTP and HTTPS traffic. I want to protect against web application attacks, but don't want to spend money for ...
2
votes
1answer
454 views

Large lan party : How to identify the users on the network?

I would like to know what are the good way to identify users on a large lan party when you manage network ? I had the idea to make the users register them self at a desk, they give us Firstname, ...
2
votes
1answer
158 views

Firewall Considerations with PGP Universal

The PGP Universal server is a fairly complex piece of work that provides several different services. When constructing firewall rules I am trying to determine what implications there are for opening ...
2
votes
1answer
2k views

Something causing Sonicwall to throw Smurf Amplification Attack Warning?

I set up a new laptop recently and, after installing various developer tools, it started causing our Sonicwall firewalls to issue an alert email whenever the laptop connected to the network. The ...
2
votes
1answer
1k views

How should I configure a Citrix Netscaler to protect against HTTP, TCP, or UDP flood attacks?

I have a Citrix Netscaler and want to configure the appliance appropriately so that it can protect my hosts from a DDOS. Is this something I can do here, or must I take action on the host itself?
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3answers
1k views

Use a Common Firewall for two Different Subnets

I want to implement a security scheme in a new network configuration. There are two buildings for the client: Office Building 1 (OB1) with address 10.0.0.0 / 255.255.255.0, Gateway 10.0.0.1 ( ...
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2answers
304 views

What compliance framework is appropriate for firewalls

As a more corpose vulnerability assessment and penetration test, one step of our activity is to review from a security perspective the policy of some firewall. In our society we have a deep ...