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Questions tagged [firewall]

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

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how do I add a correct UFW rule to allow gupnp-av-cp application to control TV on the local area network? [on hold]

I am on Ubuntu 16.04 platform. I use gupnp-av-cp application to play, pause, volume up/down, stop in short to control media buttons on TV which is connected to local area network. But When I enable ...
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17 views

Allowing exceptions (whitelist) through Google Cloud Platform IAP

My GCP project has an instance running a Jenkins server behind an IAP-protected load balancer. Adding the IAP protection has caused me 2 related issues that I didn't manage to resolve (and I guess ...
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11 views

Iptables limit flag usage

I've tried adding a iptable rule sudo iptables -A COUNTER -m limit -n --limit 1024/sec --limit-burst 1024 -j ACCEPT But when i try to see the rules using iptables-save -c or iptables -nvxL the ...
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0answers
25 views

Windows Server 2016 - Defender Firewall is not blockling inbound UDP packets to application?

Good evening! The problem: I have a Windows Server 2016 machine with Windows Defender Firewall enabled, I am trying to block inbound UDP packets to a custom network application. What I've tried: I ...
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0answers
12 views

Is it possible to skip main mode for IPSec communication on Windows?

On Linux, after registered several SAs (Security Associations) between a pair of Linux host, I can create communication between those two Linux hosts, i.e, communicate with ESP packets. But on ...
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0answers
9 views

iptables firewall not working on ftp and internet surfing on the pc server [closed]

I am new in the world of the iptables and i need to make a restrictive policy on my debian server, but is not working when i try to use ftp from windows and my website is not charging the images from ...
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28 views

ipfw not send mail to another domain

I configure ipfw for a local mail server. Everything works fine, but after a while (from one and a half days to a couple of hours) incorrect work is observed: mail from other domains comes, but mail ...
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1answer
19 views

Chrome google certificate with deep inspection

I enabled deepinspection from my firewall for HTTPS connections using a company root CA. It is well working for all sites and browsers but I found a strange behaviour by Google Chrome. When I open ...
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22 views

Connection refused from signle host Ubuntu

I have an Ubuntu 16.04 running on machine A. It has a docker container running inside of it, which exposes the port 8080 to the outside (this is where the server(Wildfly) that is running inside the ...
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0answers
23 views

Firewall cluster Active/Active [closed]

I want to make a firewall cluster with load balance and High Availability. I thought to use Proxmox for the cluster and make 2 nodes for the load balance and 2 more for the HA. The problem is, how ...
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31 views

Port 25 Connections Unknown - Should I DROP them?

I have a Zimbra Mail Server setup, and have noticed quite a few connection attempts on port 25 which are rejected because the reverse lookup fails. Here is an example output: Apr 30 06:04:48 mx1 ...
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1answer
40 views

Nginx letsencrypt certbot ssl page will not load over https but will load over http

I am trying to set up a digital ocean server using this tutorial https://www.digitalocean.com/community/tutorials/how-to-set-up-django-with-postgres-nginx-and-gunicorn-on-ubuntu-16-04 The site is ...
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14 views

Iptables / Ip6tables - a few questions

So, i was working on my iptables. #!/bin/bash iptables-restore < /etc/iptables.test.rules iptables -F iptables -X iptables -t nat -F iptables -t nat -X iptables -t mangle -F iptables -t mangle -X ...
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0answers
22 views

SSH after port change [duplicate]

I changed the SSH port on my server, but I then forgot to open a hole in the firewall for that port specifically. Now I cannot SSH into my server anymore. Is there any way around this? Thanks
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1answer
32 views

does netfilter-persistent reload open up the gates for half a moment?

I have iptables set up to block all outgoing traffic that tries escape outside my VPN connection. and netfilter-persistent to make iptables rules persistent. this all works perfectly. Now because ...
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1answer
43 views

Google Cloud Platform firewall allow os update

I have a Virtual Machine running inside Google Cloud. The VM running ubuntu v16. The machine is running behind firewall. The traffic to this machine is restricted - no outgoing traffic allowed from ...
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0answers
8 views

Manage IP ranges in Google Cloud Firewall rules

Is it possible to manage IP ranges in Google cloud Firewall rules? Something like: label the IP range 1.2.3.4/14 as office and use office in 2 separate firewall rules. This way if office IP changes it ...
0
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1answer
20 views

What is the correct port_type for rhsmd service?

I'm running RHEL 7.6 from behind a proxy. I've entered the proxy information in a few configuration files and have generally succeeded in gaining access to the rhel repositories, especially when using ...
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2answers
49 views

Windows Server Firewall: Block all incoming traffic except from domain members

I want to secure a Remote-Desktop server farm (running on Windows Server 2019). I run multiple servers with different roles (as Active Directory, Connection Broker, RD Gateway, ...). Now I want to ...
1
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1answer
137 views

VPN for Small Business - How/Who/What?

I've been reading up on VPNs for a while now and I feel like I've done circles in understanding. No one at the business has experience with networking outside of very basic home router setup. Neither ...
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2answers
87 views

drop fin packet with iptables rule

Os is linux mint 19, i want to setup a rule in iptables to drop the incomming FIN packet as a response of the FIN_WAIT_2 state. This for a given port. I want to test an application and need some ...
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1answer
51 views

How to block incoming IPv6 fragments?

I have an issue with my firewall configuration. I would like to block all IPv6 fragmented packets in a sopecific interface. So, I tried: # ip6tables -A INPUT -d <ipv6_address> -i eth0 -m ...
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1answer
41 views

Script to allow traffic to ports 53,22,443,80 and drop others, BUT I can't run apt-get update

I'm writing a script to drop all inputs and outputs traffic except traffic on those ports (53,22,80,443) but I can't apt-get update. #!/bin/sh # Flushing all rules iptables -F iptables -X # ...
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1answer
50 views

How to connect Linux Firewall IP whitelisting with database?

The problem is my dedicated box is getting ddosed. I would like to setup Linux firewall that would whitelist the ip addresses that would be listed in the database. Basically the process should be - ...
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0answers
21 views

iptables: No chain/target/match by that name., but chain EXISTS

I have created a new chain with the following command iptables -N INPUT2 I then attempted to add a fire wall rule with the following command iptables -I INPUT2 1 -p tcp --dport 22 -m conntrack -...
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1answer
61 views

Mass portscans on ephemeral ports… why?

I recently got a new account and took over management of their space, including the sonicwall. First thing's first, we updated the firmware as the prior admin hadn't been keeping up... lovely :) ...
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1answer
54 views

How should nftables rules using hostnames be rewritten to deal with multiple addresses?

I have this nftables rule: ip daddr { "0.nixos.pool.ntp.org", "1.nixos.pool.ntp.org", "2.nixos.pool.ntp.org", "3.nixos.pool.ntp.org" } udp dport ntp accept comment "Allow NTP traffic for system time" ...
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0answers
39 views

Would this setup provide adequate security?

In the following scenario, I'm looking to see if I can provide adequate security as is or if there would be any tangible benefit to re-architecting things (like changing it so that the service in ...
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0answers
18 views

Azure Service PostgreSQL deny public access

I have a question it is somehow possible to deny access from internet to PostgreSQL azure Service? Only allow it from VNET? I've read about VNet service endpoints but still not sure if this is the way,...
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1answer
97 views

Cheapest way to setup a domain controller with AD-DS for a small business with multiple locations

I work for a small business with little IT infrastructure. We want to be able to join all computers throughout the company to a single domain to push group policies and conduct other management ...
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1answer
43 views

Standard ports for web server

I'm using Hetzner for a server which only needs 80/443 and 22 accessible to the outside world. When I use the Hetzner firewall template, it also adds: protocol icmp, which I think is for ping ports ...
2
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1answer
40 views

UFW not blocking incoming traffic

I have a Debian 9 Server running UFW, and i'd like to block all incoming requests except on port 2122 (SSH), and 80/443 (For HTTP(s)). I ran the following commands : ufw reset ufw default deny ...
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0answers
35 views

Ubuntu block all outgoing connection except squid proxy traffic

i have ubuntu 14 server and i blocked all outgoing connection using ufw ufw default deny outgoing and i installed squid 3 as a proxy, i want make something like a bridge, any out going connection ...
2
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1answer
47 views

How to configure network between ec2 servers and remote workstations?

I have several ec2 servers and ten remote workstations all over the world. Both servers and workstations may be windows or linux. The servers have static IP, the workstations don't. I need to ...
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1answer
95 views

Mikrotik - Using bridge for WAN/DMZ

I'm not sure I'm going about this the right way.... I have 3 static IP's from my ISP that are all in the same subnet with the same gateway. One address is used for the router (RB3011 - 6.43.8) on a ...
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3answers
41 views

Access local server via WAN FQDN and Draytek router/firewall [duplicate]

I'm experiencing problems accessing a local server in my LAN via it's internet address. Let me explain. I have a local server, on IP 192.168.1.15, and it's serving http (port 80) (All my computers/...
2
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1answer
72 views

Barracuda “Host Access Denied”

i'm trying to setup a zabbix server behind barracuda firewall. Other configurations are working but for some reason this IP is not. "ZABBIX" on our Barracuda is a service configured in this way: The ...
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0answers
27 views

Is there a way to reserve a tcp port for an executable on a Linux Server?

I am designing a security policy for a server program on Linux. I wish to reserve a tcp port number-say 8888, to and only to that executable of the program to listen to. Then I could turn the program ...
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0answers
32 views

redirect server ip to different server if and not through the first server ip

wonder how to redirect IP from server 1 to IP in server 2 but not through the server 1. I set net.ipv4.ip_forward = 1 and I using Ubuntu Linux 16.04.5 with CSF to redirect IP 1.1.1.1 to IP 2.2.2.2 ...
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1answer
39 views

iptables egress firewall not working with IPv6

I have a server running Ubuntu 16.04 with an application that only needs outgoing connections for package updates and NTP time syncing. It has a dynamic IPv6 address on a separate network interface ...
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0answers
21 views

pfSense/UTM/any? Redirect URL:Port to internal host:port (80, 3389, etc.)

I've been trying to do this for several days to no avail. Here's my struggle: I have a few VDIs on a private server (ESXi). There's a pfSense firewall giving internal IPs to those VDIs. One of those ...
0
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1answer
51 views

Shorewall - Allow Remote Client to Ping the Internet

My network address is 192.168.5.0. My host machine is 192.168.5.1 and my client machine is 192.168.5.2. Currently, my client is unable to use the internet browser and even ping the internet. The ...
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1answer
25 views

Iptables and APF

I have a small Linux appliance where I put the iptables rule in as: iptables -R INPUT 4 -i eth0 -s XXX.XX.XX.0/24 -j ACCEPT I do a: iptables -L -v -n | more I see the rule, and it's working. ...
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0answers
16 views

IPSec WAN for Remote Access

I have hosted ERP on Separate Data center and I want to provide access for more than 300 users via Ipsec tunnel. I have no idea about IPSec WAN. Especially 150 Users are in Separate country.In ...
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1answer
29 views

Allow specific OpenVPN clients to access other clients

I have multiple OpenVPN servers which have clients like slave-1 and slave-2 which have access only to the OpenVPN server itself. I have a dedicated CA server for creating new users to the system. I ...
0
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1answer
63 views

Why isn't Fail2ban regenerating its iptables chains?

At some point while running iptables -S on an Ubuntu 18.04.2 LTS system with Fail2ban installed, I noticed that the following lines were missing: -N f2b-sshd -A f2b-sshd -j RETURN What command ...
2
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1answer
54 views

Stop Windows 10 Firewall From Asking For Admin Rights To Run Unknown Apps

one of the supplier for my company use the Software called "LogMeIn Rescue" to access the PCs of my company's employees. The problem is that everytime they launch the Software, the PC want the ...
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2answers
42 views

Corda Firewall - float

I am trying to setup the Corda Firewall, specifically the float. What doesn't seem to be clear is what is required and only required on this server/container. Trying with just the corda-bridgeserver....
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0answers
56 views

My Ubuntu server keeps “turning off” after some time

I'm new to server administration and whatever I know comes from my amateurish knowledge of linux and guides I followed online to setup an ubuntu 16.04 server for a production node app being served via ...
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1answer
56 views

Whitelisting google fonts apis on my firewall

I've got a machine behind a firewall (fortigate) that is only supposed to access a certain url, so, we whitelisted that url on the firewall and also the google dns servers: Every other traffic is ...