Concerned with software or hardware firewalls

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7
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3answers
10k views

Why do I need a firewall on my router?

I just bought a new router, and as usual the router manufacturer make a big deal out of the firewall. I have never understood why the firewall is needed, sure, stopping dos attacks (such as ...
6
votes
4answers
558 views

“There's a firewall on the router into the building so you can turn the one on your computer off”

I know some people that, in regards to network security, argue that because the firewall on the router into the building is on, that makes the network secure and therefore, the firewall on Windows ...
3
votes
1answer
2k views

w00tw00t.at.ISC.SANS.DFind iptables fix - abusable?

It's only an idea. I've recently logged that my server is scanned by w00tw00t tools. I found many solutions to this, such as use of apache mod-security, fail2ban, etc.. The one I want to speak ...
2
votes
1answer
610 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, ...
4
votes
3answers
4k views

Which of these ports are safe to leave open, which are not?

I just ran nMap against my IP address and got the following result: PORT STATE SERVICE 21/tcp open ftp 22/tcp open ssh 23/tcp open telnet 80/tcp open http 443/tcp open https ...
3
votes
1answer
2k views

How can I find the process that is trying to use smtp to send email?

Previously I asked Who (which process) is calling curl? and I got very good answers (this answer in particular) which basically replace the curl binary with a shell script that logs each call to curl ...
1
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2answers
5k views

What needs to be done on a Citrix Netscaler to protect from SSL Renegotiation attacks?

I'm under the impression that the TLS/SSL renegotiation hack has been fixed. I'm not sure if the software has to be deployed on the server side, client side, or both. Based on this blog, TLS ...
2
votes
1answer
206 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 ...
0
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1answer
863 views

Cisco PIX SNMP enabled or not?

On a Cisco PIX firewall, I wanted to check if SNMP is enabled: pix# sh snmp-server no snmp-server location no snmp-server contact snmp-server community public no ...
5
votes
1answer
1k views

Why ESTABLISHED,RELATED for INPUT only?

In many places and tutorials I see people add this line to their iptables: -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT And they do it only and only for "INPUT". What about OUTPUT and ...
0
votes
1answer
224 views

FoundStone scan + URI filtering

I have a server that is protected with a firewall with URI filtering rule. So if you go http://x.x.x.x/URIFilter/Something you will get to the server, but if you don't put URIfilter into URL or use ...
2
votes
1answer
3k 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 ...
8
votes
1answer
441 views

Is Chinese great firewall white or black list based? [closed]

Is a new website blocked by default in China ? I just put online a new website dedicated to chinese people (a working days calculator in China, nothing subversive indeed). However a friend of a ...
4
votes
1answer
213 views

firewall with cloud based malware analysis risks

Palo Alto, and probably others firewalls will offer it, has a feature to do malware analysis in a separate (cloud-based) process that does not impact stream processing. What I would like which risks ...
2
votes
1answer
2k 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?
4
votes
1answer
7k views

Fail2Ban does not ban failed root login attempt

I have a small server which only open ports are ssh, http and https. I have fail2ban installed and set up so that after 3 failed attempts someone gets blocked for 10 minutes (thats the dafault I ...
5
votes
4answers
2k views

Security concerns from publicly visible Hudson & Jenkins servers?

A friend's start-up has implemented a number of business critical services on a Hudson/Jenkins server run on a Tomcat container. This is not an open-source project, in fact many aspects of this ...
0
votes
1answer
3k views

i, I, o, O packet inspection points inside a Check Point firewall

In a Check Point firewall, can you please explain what occurs between the POSTIN (I) and PREOUT (o) inspection points?
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 ...
0
votes
1answer
2k views

windows security alert windows firewall has blocked some features of this program message coming for every new build of my application

I made an application which uses ftp so windows shows windows security alert windows firewall has blocked some features of this program message for every new version of my application any idea how to ...
3
votes
3answers
4k views

is it worth to implement a firewall on a web server you control?

I see the main reasons for a firewall on a web server to be defense in depth and extra cushion for a possible admin error of running an unnecessary daemon. I'm trying to see if I am overlooking ...
1
vote
1answer
820 views

Client access to domain controller

I'm working on a solution to identify if a machine is a member of the domain or not. We are using Checkpoint R75 Identity Awareness with two possible methods to retrieve machine identity. AD Query ...
6
votes
2answers
1k views

Network Vulnerability Scanner placement on network

We have implemented/are implementing a network vulnerability scanning process, and we have chosen to use Qualysguard. Qualys supply a scanner appliance for the internal network scanning, which ...
9
votes
3answers
11k views

Proxy vs. Firewall

I understand that very simply put a proxy is a sort of 'man in the middle' allowing/denying access to certain services/resources. Strictly in terms of security (I mean here privacy, parental control ...
21
votes
6answers
4k views

What is the difference between $200 and $1,000+ Firewalls?

Instead of asking about the pros and cons of specific hardware, I thought I would ask a broader question: What are the differences between really expensive and inexpensive firewalls? What extra ...
7
votes
3answers
626 views

Firewall says that a program that I'm developing is trying to connect to the Internet

I'm seriously confused about this, since the program is entirely developed by myself and has no means/functionality to connect to any network/the internet whatsoever. I'm a software engineer but not ...
2
votes
4answers
2k 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 ...
3
votes
1answer
4k views

Is opening both TCP/UDP less secured than just TCP or UDP when needed and why?

If application needs opened port X UDP, or X TCP combination. Is there any potential risk by opening both UDP/TCP as I usually am not sure which one the application uses?
3
votes
1answer
866 views

Mac sending hundreds of packets to gateway

I've got a user on my work network who brings her personal laptop (macbook) in for work. They've been having some horrendously slow network issues on everything past that hub, so I did some packet ...
10
votes
3answers
10k views

How to listen to all ports (UDP and TCP) or make them all appear open (linux)

I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
15
votes
5answers
18k views

What is the best practice for placing database servers in secure network topologies

I have a classic DMZ architecture: My webserver is placed in the DMZ. The webserver needs to communicate with a database server. This database server is the most critical component of my network ...
4
votes
2answers
569 views

What is the background of the Reference Counter Overflow in Microsoft TCP/IP (MS11-083)?

How unique is this bug? Is there a more sophisticated and well-studied attempt behind? Is it accidence? The article below says "continouos stream to UDP". What stream? Just an hour stream of zeros? ...
4
votes
1answer
780 views

IP address filtering vs web application security

We have a web application behind a firewall that requires no user authentication. If we open up access to this application via the firewall to a small list of IP addresses what is the risk of ...
14
votes
6answers
13k views

How important is NAT as a security layer?

I've signed on to help a department move buildings and upgrade their dated infrastructure. This department has about 40 employees, 25 desktops, an old Novell server, and a handful of laboratory ...
4
votes
2answers
617 views

Firewall design for big enterprise business

I am wondering if there is any best practice firewalling rules that should be put in effect in most modern networks. For example should the network atleast have the following firewall zones? Client ...
5
votes
1answer
1k views

I'm having a DDoS attack, my hosting company is stupid, and I need to know what is hapening

So ok, right now my windows 2003 dedicated server is under attack by some guy who's flooding UDP packets (~90.000 packets/sec) on my 100Mbps server for the last 8 hours. I'm on a shared port, so I'm ...
6
votes
2answers
1k views

How do experienced users test stateful firewall?

How do experienced users test stateful firewall with TCP/IPv6? My test case includes: echo reply without request tcp ack without syn Are there any more test cases, especially with IPv6?
8
votes
4answers
3k views

Is Windows Firewall suitable for running in a production environment?

Is Windows Firewall suitable for running as the sole protection on a production web server? Is it hardened enough? Robust enough? and tested enough? I'm running a VPS with Rackspace on their cloud ...
1
vote
0answers
396 views

PF NFS Firewall Issue [closed]

I have a question about NFS and PF (freebsd). I know that NFS uses both TCP and UDP to connect to the client along with a bunch of daemons that use random port numbers. Both the NFS server and ...
6
votes
2answers
3k views

I'm getting lots of unfamiliar connection attempts, what do I do?

I'm running Mac OS X and I have the system firewall enabled and I have stealth mode enabled. I opened up my system console and noticed that I'm getting tons of blocked connection attempts from places ...
7
votes
1answer
5k views

How is tunnelling SSH through Poxytunnel/HTTPS different from doing it through SSL with Stunnel?

In an answer to What is the difference between SSL, TLS, and HTTPS, it's said that HTTPS is HTTP over SSL/TLS. That is, an SSL/TLS connection is established first, and then normal HTTP data is ...
8
votes
5answers
7k views

What kind of attacks against home router's NAT do exist?

I always thought NAT was some kind of a security feature and I still think it is, because if it didn't existed the internet, respectively the clients behind NATs, would be even more insecure, since ...
3
votes
4answers
412 views

What does a switched network protect us from? What does it not protect us from?

There seems to be some misconceptions regarding what a switched network will protect us from, and what technologies/precautions a secure environment requires when segmenting trusted users from hostile ...
4
votes
3answers
668 views

Servers: Why a separate device for a firewall, aside from reduction in IP spoofing or increase in performance

Why should the firewall be outside the server, excepting these two items Take the performance impact of noise off of the server. Add a physical layer between devices so they can be on separate ...
5
votes
5answers
2k views

What are the likely threats to a public-facing DB instance?

Quick intro: Small company, VERY limited resources. I pretty much do everything including take out the trash. We've been running an instance of MySQL internally for years and it's worked OK, but I ...
3
votes
2answers
2k views

Reverse shell connections

Why are reverse shell connections so popular in the event of a successful intrusion? Many "hacking" videos show this and it is often seen in practice. Would not most servers restrict outgoing ...
1
vote
3answers
3k views

Power friendly home router, firewall, IDS/IPS setup? [closed]

For those that like to manage their own firewall and run IDS/IPS on their home networks, I'm curious - what are you using and is it power friendly? I used to have a shelf full systems doing various ...
10
votes
7answers
4k views

What security implications are there for allowing outbound SSH traffic?

My school currently blocks outbound SSH traffic. Users inside the network cannot use Port 22, and attempting to make an SSH connection over another port is also blocked. (I'm assuming the firewall ...
2
votes
5answers
645 views

How do a firewall's rules for individual programs work?

I kind of know that how a firewall's rules for IP/port work, but I have no idea how a firewall deals with individual programs. In other words, how does the firewall know a program wants to access the ...
2
votes
3answers
2k 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 ( ...