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Questions tagged [firewalls]

Concerned with software or hardware firewalls

4
votes
1answer
134 views

Using a bastion server: how to model an emergency entrance?

I have set up a bastion server (A) that acts as the only "hallway" to enter a bunch of other private VPS's (B). That is to say: the private machines only accept SSH-connections from (A) on a non-...
9
votes
1answer
1k views

Nmap - Intense vs Quick result

I inherited a small network and currently am assessing its security performance. I started port scanning a host (lets call it Weirdo) in that small network and from my perspective, it seems that that ...
1
vote
0answers
117 views

Securing a private network: how-to [closed]

I have the following setup: Net1 -> Router-net1 (w/firewall) -> Net2 -> firewall -> Internet In Net1 I have several machines I use to run experiments. I would like to minimise the risk of ...
1
vote
0answers
137 views

Bypassing Client firewall restrictions

Lets suppose we have 2 parties A(me) and B(participant). I want to communicate with B but B's firewall restrictions are not allowing me to communicate with him. Is there any way that I can bypass B's ...
1
vote
3answers
372 views

How to secure my network and system setup? [closed]

I have 2 severs and 12 systems (All having UBUNTU) connected to each other over LAN. The 12 systems use multiple databases (Redis/Postgres etc.) hosted on the 2 servers using LAN. Now, I need to ...
5
votes
2answers
10k views

How to directly connect to devices behind NAT from the internet?

We have an IP address on the global internet: "A" We only have access to "A". We have a network behind a router that does NAT: 192.168.1.0/24 There is a client behind that NAT: "B" We don't have ...
3
votes
1answer
370 views

Protecting web site with nginx 301 redirect and HTTP firewall

I am setting up a hobby web site and trying to make it as secure as possible. The backend is nginx + uwsgi. I have set up the HTTPS connection. For non-SSL requests, I have the following rules in ...
2
votes
2answers
444 views

On the days of stateless firewalls, was there any reason for using firewall in the place of router?

The first generation of firewalls was only simple layer 3 device with multiple interfaces and access list applied in/out direction on the interface, during the same era the routers was supporting also ...
1
vote
0answers
46 views

Firewall rulebase analysis offline/vendor agnostic a thing for FISMA/NIST

During design-time before a build-out, I currently create an excel file version of a firewall rulebase (policy) representing source/target/port/protocol/etc definitions before being pushed to the ...
1
vote
1answer
729 views

Can I control network traffic or bandwidth using router? [closed]

That's the question I have access to the Arris router of a lan there are several options like DMZ, UPNP, Firewall and others. I want get a more large bandwidth of my internet for faster download on my ...
1
vote
0answers
177 views

UFW behind modem does not block remote IP

I have a small linux server with fail2ban and UFW installed and configured behind internet gateway modem which ssh port is forwarded to server. The attackers are discovering by fail2ban and added to ...
2
votes
1answer
130 views

Which set of rules is more restrictive when allowing SSH in iptables?

I have seen two set of rules to allow SSH communication: Set A: iptables -A INPUT -p tcp --dport 22 -j ACCEPT iptables -A OUTPUT -p tcp --dport 22 -j ACCEPT Set B: iptables -A INPUT -m state --...
1
vote
3answers
126 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
189 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
votes
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
vote
1answer
131 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
116 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
264 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)?
0
votes
2answers
420 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 ...
-1
votes
0answers
190 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
101 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
votes
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
4k 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
297 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
vote
3answers
553 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?
1
vote
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
764 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
431 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
votes
2answers
4k 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
vote
1answer
146 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
vote
2answers
1k 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
votes
2answers
80 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
vote
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
vote
2answers
507 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
838 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
votes
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
745 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
votes
2answers
427 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
vote
2answers
346 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
3k 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
192 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
144 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
votes
1answer
319 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?...
2
votes
3answers
6k 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
171 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
211 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 ...