Questions tagged [firewall]

A Firewall is an application or hardware device used to inspect and filter network traffic.

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Google Cloud IKEv2 VPN on Ubuntu Compute Engine VPS

As I stated in the title, I am installing the strongSwan and configure the IKEV2 VPN on the VPS. But, as you know, GCP has its firewall rules, which I am not familiar with that. I am using this ...
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openvpn restricting clients from accessing certain IP's in internet with ufw

I'am looking for a solution which can block openvpn clients in accessing certain website(ip's) in internet, i tried ufw rules like below , but doesnt seems to work from client, what piece do i miss? ...
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How to use defined variables in Nftables though terminal (not in script)

I want to run these two commands in a interactive shell, one after the other (as root and with the "filter" table and the "input" chain loaded): nft define lala=1.2.3.4 nft add rule ip filter input ...
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How we have differentiate the packet capture based on the RX & TX

I am working in the security industry. We have taken packet capture on the firewall multiple times. Can we take Pcap based on RX and & tx and force the tcpdump command to write the output in two ...
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Windows firewall outgoing rule exception not working

I set custom outbound firewall rule on Windows Server 2019 which deny all outgoing traffic on 192.168.2.0/24. The rule is working for all until I set an exception in "Local principal/Exceptions". When ...
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Firewall not allowing DNS resolution

I have the following network on the firewall Infrastructure - 192.168.10.0/24 Gateway 192.168.10.1 (firewall interface 1) DNS Server 192.168.10.2 HostsA - 192.168.20.0/24 Gateway 192.168.20.1 (...
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AWS WAFV2: ACL Rule for allowing access to specific URI Path

I have some web acl managed rules in AWS ELB that are blocking webhooks from Pusher api. They don't provide an IP list that I could include in a white list. I'm trying to create my own rule to allow ...
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How to use IPTables to keep a running total of the amount of data passed to and from a single IP?

I need to keep a running total of the number of bytes passed between my server and a remote server (port unspecific). I would like to keep this running total written in a file. I'm a bit new to ...
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Does an IPSEC tunnel establish new sessions for traffic?

Background AT&T business fiber is basically rebranded U-Verse home internet. The "modem" (it's actually a router, but lets call it that for simplicity) has a hard limit of about 8K sessions. Even ...
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Blocking requests via Cloudflare at the firewall (not web server) level

The broad context here is that I wish for the firewall (pf) to be able to ban certain IP's from accessing the website. I first restore the origin IP in the web-server (Nginx) logs. Then I use ...
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Restoring default iptable rules after complete wipeout

I am a complete newbie who just accidentally erased all their desktop's iptable chains and rules and wants to restore them all to the previous default (docker nor bootstraps work now as they cannot ...
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Which port should you left open for inbound and outbound for other Linux services to work properly?

I am going to deploy a docker swarm (3 node: 1 manager 'frontend', 2 worker 'backend and db') with Security Groups for the VPC. I am planning to deny all inbound/outbound connection from the start. ...
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Can't access tomcat externally in Centos 7

I just installed tomcat 8 on a Centos 7 server and I know it's working because I could get tomcat's index.html with wget http://localhost:8080. (I couldn't think of another way of testing in a remote ...
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OpenVPN Server Routing/Firewall Settings [closed]

Short Desc: Connecting Rasp pi 3 as client to data center dedicated server for pulling backups over rsync. Getting "ERROR: Cannot ioctl TUNSETIFF tun0: Device or resource busy (errno=16)" Long Desc: ...
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Windows GPO firewall settings not working

I have set my GPO to add two firewall exceptions (under the same one that adds my network drive which works every time and I know it is executing them), but it does not seem to work. I have even tried ...
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Nftables - how not to dnat an ip on interface (DNS)

I have been searching, but cannot seem to find an answer to my specific issue. I have the following rule today under prerouting: iifname "br0" udp dport 53 counter dnat to 192.168.22.5:53 However, I ...
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dual ISP firewall cluster in linux

For the past couple of weeks i have been trying to figure out how to make firewall cluster, each having different ISP. I have found few guides on how to do it with one ISP using technologies like ...
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Do I have the right IpTables here? I cannot send but I can receive

Setting up a mailserver and I've taken steps to secure it. One of the steps is to have a set of IPTABLES rules From you can see, I've set all the policies to DROP, even the OUTPUT, I think that's ...
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Can I still add firewall rules on command line if I use webmin

Was wondering what is the relationship between Wembin->Networking->Linux firewall and adding firewall rules using the command line. I ask this as I want to add a firewall rule like iptables -t nat -...
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How to allow access to my gcloud appengine apis using a specific port other than the default port 443

I've already tried to configure the firewall and I still can't access using the port other than the default port
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How to reliably block sensitive content on twitter?

Since the introduction of twitters content policy, possibly sensitive content is marked and users have to skip the warning to actually see the tweet. Is there a way to block possibly sensitive tweets ...
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iptables: setting specific rules to IP aliases

We run several game servers all using one port with the use of IP Aliasing, the game servers bind to a specific aliased IP that belongs to the main dedicated server. I've setup netplan already and it ...
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Redirect localhost port to external ip and port

I am running macOS Mojave 10.14.6. I have an app that is looking for a service hosted on localhost:9999, but I am hosting this service on a different server at 12.3.4.5:8000. How can I setup firewall ...
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Ufw and Iptables. Which is better and why? [closed]

I am a newbie to this domain, so i kept researching on ufw and iptables. But I cant distinguish them clearly because in every article /blog both of these names are present and I am really confused ...
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Proxy Azure SQL database with firewall enabled on IP range

I have following setup Azure SQL Database with firewall enabled, so that it will allow connections only from 104.x.x.x IP addresses Azure hosted Linux VM, within the same location as Azure DB, with ...
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Can't connect to SQL Server 1433 port for VM windows server externally on gcloud

I have already enabled the port in the firewall rules in gcloud, windows server and instance. I defined the port in the sql configuration manager. The other ports like 8080, 23, 21 are working ...
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How to block Internet Traffic to MySQL on Ubuntu 18.04

I have setup two KVM servers with a local hosting service. They provide me with one public IP per server. I installed mysql-server 8 on one of them. Before describing the issue, here's the result I'm ...
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Single VPS, multiple IPs - different iptables rules based on IP

I currently have a VPS with just 1 IP address and I want to buy another IP and do the following: have one public IP with incoming requests allowed only on port 7777 (UDP) have a Mysql server running ...
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CSF (ControllServer Firewall) banning cloudflare ip not real ip addess

I got a ddos attack on my website earlier today which is using cloudflare. The attack was some kind of flood by visiting the page too many times and cloudflare wouldn't stop it. I'm using CENTOS 7.7 [...
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random ufw rule disappears at various intervals

I'm becoming mad because of the following problem. machine: VM with 1GB RAM, Debian 10, updated packages running just sshd, postfix, fail2ban, nagios-nrpe and ufw Issue: there are several ufw rules, ...
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How can I setup a dual SSH tunnel so that two machines A and B behind firewalls ssh into a central sever such that A can VNC into B?

I need to connect via VNC from my machine A to another machine belonging to my friend B. Both of us have no way to open incoming ports - ISPs do not allow tunneling unless you buy a static IP based ...
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Windows Firewall - Block all incoming traffic on Interface 1

I have a Windows Server (2019) with two interfaces. The first Interface is for Internet access only and the second for management only. Now I want to block all incoming connections on the first ...
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Cannot send TLS emails

I just migrated to a new server. With it I have problems sending TLS emails. I made a php code to test it as bellow: <?php require 'PHPMailerAutoload.php'; $missatge_complet = "HOLA"; ...
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1answer
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Which firewall port required to access python repository?

Trying to install python library from corporate Server. Due to security reason the internet is blocked and specific URL's only allowed. So would like to raise a firewall opening to install python lib ...
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Prioritizing an Interface on VyOS

I have a VyOS router which has three interfaces--one connecting to a guest network, one connecting to a business network, and one connecting to the open internet. The business network will not take up ...
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DNS behind NAT (PowerDNS)

I'm having two different locations for DNS servers. I'm using PowerDNS. Locally everything works fine, but when I want to update from the Master the update over Internet is not working. I'm using on ...
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Would there be less load on a NAT firewall if some or all of the traffic were routed over IPV6 Instead of IPV4?

Just curious.. I was thinking that, on a NAT firewall that is normally overloaded, offloading some or all of the IPV4 traffic to IPV6 might make a performance difference?
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Weird TCP/IP behavior on Linux server as well as enterprise Firewall on port 21

This is a tricky one. TL;DR: 1) Client establishes TCP handshake with the firewall on (closed/unavailable) port 21, even though firewall does not respond to client's SYN packet. 2) Client ...
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Error with CSF on ubuntu / firewall

it turns out that on the PC of the "physical firewall" I have CSF installed to control all incoming traffic, and from there I route the ports to different applications located on other machines to the ...
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Mac OS pf redirect error cksum incorrect

Scenario Server A - 192.168.43.215 - listens on port 4000 Client B - 192.168.43.207 - Mac OS 10.14.6 I want: connection to B at localhost:8080 ---> A:4000 ex: following command on B's terminal ...
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`ufw default deny outgoing` breaks sshuttle

sshuttle is this During the following process the content of my /etc/resolv.conf is: nameserver 1.1.1.1 Here is my initial ufw rules: Status: active Logging: on (medium) Default: deny (incoming), ...
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Connection timeout trying to access Webmin on port 10000 in CentOS 7

I'm trying to install Webmin so I can have a graphical interface to manage the websites on my server. By default, it should be accessible at port 10000. When I try to access it at http://myipaddress:...
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819 views

Routing via gateway to another subnet - firewall builder

the question is very similar to the one posted here: Routing via gateway to another subnet My question is about the correct routing / iptable settings for the following network topology, which ...
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How to limit ICMP Echo requests to 5, then drop for at least 30s (if the pings stop) with iptables?

I tried it with following 2 lines iptables -A INPUT -p icmp --icmp-type 8 -i $EXT -m recent --set -j ACCEPT iptables -A INPUT -p icmp --icmp-type 8 -i $EXT -m recent --update --hitcount 5 --seconds ...
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Sandbox/firewall process to only connect to specific IP or host in Debian Linux

Under Linux (Debian 10), I would like to sandbox a program started via a shell script, so that it can only open a connection to a specific IP address or host, but not to any other. I am looking for a ...
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Cisco ASA 5506-X Bridging on same subnet

Is it possible to configure an ASA 5506-x to have both inside and outside interfaces in the same subnet? Our outside interface connects to a VPN and is supposed to act like a point-to-point connection ...
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GPO firewall rules applied in random order

Does GPO precedence not apply to firewall rules? We want three firewall rules for most PCs, and different rules for some PCs in an OU. That should be easy because a GPO linked in the OU should take ...
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Firewalling a BGP daemon (bird, port 179) with iptables in anycast scenario

I have a bunch of globally distributed servers which share an IP address using BGP Anycast. Each server announces itself to the next router using the bird BGP daemon. The daemon runs on port 179: # ...
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Is there a need for the nat table INPUT chain?

The iptables man page suggests the following standard tables and chains: raw mangle nat filter PREROUTING X X X INPUT X X ...
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UFW/Iptables: Allow response to http(s) requests but block everything else

I'd like to block everything outgoing from my server while still allowing responses to incoming http/https requests. Some examples: User calls my server using his browser (https://myserver.example....

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