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Questions tagged [firewalls]

Concerned with software or hardware firewalls

1
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3answers
117 views

How to prevent DDoS to cause stored data inconveniences?

Let's assume there are no vulnerabilities in the application layer, one disk, and no physical firewall (just iptables rules in the server itself), hence in this case all the DDoS attack does is to ...
2
votes
1answer
181 views

Fixing an OpenSSL vulnerability at the firewall

We did a Qualys test on two of our URLs earlier today. The URLs are of two similar applications (same versions) hosted on identical servers located at two different datacenters. The test returned 'A-' ...
3
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2answers
2k views

MAC filtering the internet traffic?

I was trying to build a firewall where in the access to my LAN from internet should be allowed only if it matches the predefined MAC address of the device i.e,. MAC filtering, but later i found out ...
1
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1answer
120 views

nmap - protocol discovery doesn't work with fragmented packets

Using nmap to do a protocol discovery (nmap myhost -sO) identifies the following on my target. Note reason switch is also used. PROTOCOL STATE SERVICE REASON 1 open icmp echo-reply ttl ...
1
vote
1answer
115 views

Can any web proxies differentiate between JScript and Javascript files?

Its a relatively common best practice to filter executables and scripts from a standard user at the proxy/gateway level in corporate environment. While EXE/BAT/CMD files are easy enough, and arguably ....
2
votes
1answer
257 views

What is UDP port 56183

We seen suspicious probing from source port 53 to destination port 56183. May I know what services use port 56183 (udp)?
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2answers
378 views

Are there any PCI compliant firewalls that can be installed on Linux through normal means and not through an ISO? [closed]

We are trying to install a PCI compliant firewall on our Azure Vnet. The problem is, that ones like opnsense can only be installed through an iso, having to install it on a local VM and then having to ...
0
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0answers
171 views

Centrally push changes to multiple firewall devices (checkpoint network, iptables/firewalld host)

Pleading ignorance here - are there any ways to centrally pull current rules from multiple firewall devices (such as checkpoint network appliances, and iptables or near-future firewalld host rules), ...
2
votes
2answers
100 views

What methods could be used to host on an infected machine?

Assuming the following: a computer is compromised and connected to a network where a simple wireless router or modem is the only form of firewall security all incoming connections are blocked by ...
2
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0answers
64 views

WiFi access points blocking VPN [duplicate]

I've been travelling for awhile and used a lot of Wifi access point lately. Several times my attempts to connect with VPN has been blocked (especially when using a "famous" one), and I've also noticed ...
0
votes
1answer
3k views

Difference between stateful and stateless firewall filters

Stateful filters keep a "list" of already established connections, and if the connection is being established, what step of the TCP handshake we are on (SYN, SYN ACK etc.). Stateful is supposed better ...
1
vote
1answer
264 views

How application-level stateful firewall impacts network performance

For the "application-level stateful firewall", I mean: the firewall inspects the application-layer payload (e.g. deep packet inspection), memorize the status using some parameters, and store it in ...
1
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2answers
444 views

Windows firewall blocking of a dynamically generated .exe

If I block application A.exe on my firewall, but it dynamically generates B.exe and runs it automatically. Would B.exe also be blocked on my firewall?
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0answers
1k views

Different filtering techniques with internal and external firewall?

First of all, lets get the basic information sorted out. Just in case I have it mixed up. There is an external Firewall - Router (or some such device), and there is an internal Firewall (an ...
0
votes
2answers
698 views

Firewall is blocking invalid URLs, what is the danger?

My Fortinet firewall seems to be blocking invalid URLs (for example, URLs that it considers invalid, which means that underscores are not accepted, even though some sites use them). This causes some ...
1
vote
3answers
381 views

boundary firewall cyber essentials question

I have been going through the cyber essentials questionnaire and this one question is confusing me and I wondered if you could provide any insight into it for me. in one of the 5 sections 'Boundary ...
4
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2answers
3k views

Block outgoing network traffic from “Smart” TV

The FTC has just settled a case with Vizio, saying that the company has been quietly capturing pixels from their smart TVs, matching those pixels to databases of content, and selling that information (...
1
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1answer
145 views

What security issues are there with remote access for firewalls, routers, etc.?

I am currently looking into cybersecurity for small businesses and it is something I have become very interested in. One of the questions in the questionnaire is: Confirm that any remote ...
1
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2answers
985 views

Are there risks to allowing cURL from my machine?

I currently have several update scripts that I run periodically, which use curl to pull and install updates from various places. In my current configuration however, I have curl blocked by my firewall,...
0
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2answers
78 views

Accessing another host in an wifi network

In a public wi-fi network if I know the IP of another host/laptop on that network I can add a default route in my host to that IP. Will this allow me to access services (or even the corporate network ...
1
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0answers
42 views

Objectively speaking, what is the expected standard to prepare for an interview as network admin? [closed]

I have an interview middle of next month for a position as network admin. As I understand things, clients are running Windows but some servers may be running Linux. What is the expected standard in ...
1
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2answers
464 views

Allow DELETE method over firewall WEB API 2

I am working with a ASP.Net Web API 2 service and the firewall denies the DELETE method to go through (only POST and GET are allowed). Is there a way that we can bypass this and invoke my DELETE ...
0
votes
2answers
797 views

Bitdefender detected over a hundred port scans and still detects, what does that mean and what should I do?

I have Bitdefender Total Security 2017 installed on my computer and today especially in the last 10 minutes I got over a hundred port scans (detected and blocked) which is weird cause I usually get ...
2
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1answer
1k views

Firewall topologies (Screened Host vs Screened Subnet vs Dual Homed Host)

I'm wondering, if I enable access to an internal web server through my home router / firewall via port forwarding. Which firewall architecture corresponds to this setup? Screened Host, Screened ...
3
votes
2answers
678 views

By how much does virtualizing a perimeter firewall reduce network security?

I am looking to set up a hardware firewall for my home network. However, I am but a poor lowly student so I'm looking to virtualise to reduce hardware costs. Now for a diagram to explain what I have ...
1
vote
1answer
103 views

Does routers, firewalls log dedicated server connections?

I would like to learn about logging policy of datacenters about dedicated servers? Is it possible to log every connection/port to dedicated servers by datacenters with using routers/firewalls? Or is ...
0
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2answers
355 views

Setting up communication between internal database and hosted web server by third party

I am trying to figure out the best and most secure way to do this, if it is possible to do it safe and secure. Small company. We have a hosted web server from a third party that serves our client web ...
1
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2answers
309 views

Is the IPS SQL Injection Prevention in my firewall overly aggressive?

I have a firewall with some packet inspection configured to detect SQL Injection attacks. (Dell SonicWall NSA 3500) There is a rule (HTTP Request URI with SQL Statement (IF) 2) that seems to consider ...
3
votes
2answers
2k views

Blocking Windows 10 telemetry destinations with Windows Firewall

Is is effective at all? As it commonly known, Windows introduced plenty of allegedly diagnostics collection tools which collect our private data and send this info to MS servers. Is it efficient and ...
0
votes
2answers
187 views

How much traffic can a firewall node handle? Any real examples? [closed]

As a part of my research, I need to determine the maximum packets (Internet traffic) can one instance of firewall/ IDS process. I am not sure where to begin though. Your assistance and guidance in ...
3
votes
1answer
141 views

Enterprise Network Security - Firewalls for a small environment

Good day. I am the IT Manager at work and we are looking to enhance the security of our infrastructure given the sensitive nature of the data we house. We have a small environment consisting of a few ...
4
votes
1answer
2k views

I want to restrict access to Nextcloud using OpenVPN

Is it a good idea to restrict access to my Nextcloud server by using OpenVPN, so every user (this is for small group of people), will get their own VPN account and after that they will be able to ...
26
votes
8answers
6k views

How to respond to a SSH brute force attack on a single VPS?

I logged onto my VPS this morning to find millions of failed login attempts for the root user and other users that don't even exist. I took the below measures to try and obfuscate the attackers ...
5
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1answer
277 views

Firewalling: Screened Host / Bastion Host

I'm having troubles understanding the definition or the idea behind screened host / bastion host that you often find in the internet or books: Is the bastion host in this context, the firewall itself?...
1
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3answers
5k views

Does an open port with no service listening on it pose a risk? [duplicate]

I have a home server running Ubuntu 16.04 Server Edition. I have a couple ports that my router forwards to my server and ufw on my server allows so that I can access the services outside the LAN - ...
1
vote
1answer
1k views

Why can't I delete the default AWS security group?

There are no inbound nor outbound rules. It's an empty group. What use does it serve?
3
votes
1answer
164 views

Could encryption become a security breach?

So, I was skimming though this SANS research about skype . Long story short, it says : Skype uses standard cryptographic primitives to achieve strong end-to-end encryption (Berson, 2005).........
3
votes
1answer
210 views

Firefox redirecting to other webpages and Adobe Flash Player plugin update button redirects to other webpage (not the adobe offical page) [duplicate]

When I try to update the Adobe Flash Player plugin for Firefox by clicking on the button for updating the plugin, it redirects to itsmyviews.com. In addition, when I visit the any site, my browser ...
2
votes
1answer
1k views

Does a Server connecting to port 3544 pose an increased risk

I had look at the firewall logs and i can see my production server connects to microsoft (13.92.90.48) on UDP port 3544. A quick reading suggests this is to do with Teredo tunneling (IPV6 translation ...
2
votes
1answer
39 views

SPAN traffic for “Internet to Ext FW”

Is it advisable to mirror the traffic between the internet and the external firewall while the management interface is accessible from within the network? This is to perform packet capture and ...
7
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1answer
509 views

In IPSec what is the definition & purpose of SAD and SPD?

What is a Security Application Database & Security Policy Database? What is their role in processing models for OUTBOUND and INBOUND packets?
23
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7answers
3k views

How can I publish data from a private network without adding a bidirectional link to another network

I was just wondering how I could build a private network where it is physically impossible to gain access from outside but still have the option to publish data to some remote server. As an example: ...
-4
votes
2answers
646 views

Why is it a bad idea to allow all inbound / outbound traffic?

I have an AWS server. I didn't want to spend too much time configuring the Security Group and allowed all inbound and all outbound traffic. Is this OK or is it a bad idea?
2
votes
0answers
269 views

Blocking Multiple Failed Postfix AUTH Attempts with CSF

I am using CSF/LFD on my CentOS 7 server, and would like to use it to temporarily block IP addresses that have multiple failed Postfix AUTH attempts. You know the one, I get line after line of: lost ...
0
votes
1answer
169 views

Network Routing through Proxy to VPN

(This is *somewhat* of an extension to this question.) I've come to enjoy (yes, I know) using a VPN for all of my internet usage (specifically Freedome), but I don't have a lot of money to buy ...
1
vote
2answers
678 views

Nmap results of home network

I've been trying to up my security recently and decided to check my router's firewall by doing an nmap scan (wan). I'm surprised by home many ports it found: Host is up (0.032s latency). Not shown: ...
4
votes
1answer
658 views

How to prevent ICMP redirection produced by a man-in-the-middle

How can I prevent my route to be redirected with redirecting ICMP packets from a man-in-the-middle? I am specifically looking to avoid someone using ettercap with the -M icmp option. From man ...
0
votes
1answer
158 views

Attacking (or even pinging) a device over a network on different VLAN

If a firewall is configured with different VLANs, how could an attacker perform an attack over a different VLAN. I see a lot of information on scanning, exploiting, and other attacking methods using a ...
1
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0answers
76 views

Simple DMZ Question Regarding Physical Hardware

So when talking about at setting up a DMZ, if you are currently running a web server, app server, and a database server on the same physical host, you need to migrate them to separate physical hosts ...
0
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1answer
524 views

Stateful vs Stateless *host* firewall - is there any advantage?

In the case of a firewall device seperate from a server host, I believe there is a clear benefit to using a stateful firewall. But in the case of a host firewall, where the services in scope are ...