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linux + how to close connection that are not in used

from netstat -anp | grep :8088 | grep EST we can see the following connection ( is example from our hadoop server ) tcp 0 0 192.83.23.112:42360 192.83.66.114:8088 ESTABLISHED ...
yael's user avatar
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1 answer
64 views

What is a port?

I have been running an Apache web server for numerous years and have been using ports as a medium to serve requests. Recently, I began using Unix sockets to serve MySQL requests. The function of Unix ...
user10709800's user avatar
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0 answers
65 views

How to assign virtual IP address from a router

My home network looks like this: Everything is GNU/Linux and network-sharing is setup using networkmanager with nmtui, I have no experience with any other tools. I need to access router A from PC ...
amp-likes-linux's user avatar
0 votes
1 answer
76 views

"Connection refused lost connection" error while using scp command

I tried to transfer a file from an HPC system to a remote CentOS system using the following command line: scp /ANKAN/data/abc.pdf [email protected]:/data/ANKAN But I am getting the following ...
Ankan Sarkar's user avatar
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0 answers
33 views

Cannot get wireguard to connect [duplicate]

I'm trying to turn my pi into a home VPN with wireguard, but cannot get it to work, despite not receiving any errors. My pi is connected to my home router via Ethernet cable, and is given ip 192.168.1....
Rachel1983's user avatar
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1 answer
180 views

Why does Wireguard break my internet access when I run wg-quick up wg0

Im trying to use my raspberry pi as a wireguard server. When connecting my raspberry Pi to my router via Ethernet cable, my router assigns pi to ip 192.168.1.35 Ive confirmed the pi receives internet ...
Rachel1983's user avatar
0 votes
2 answers
138 views

Where does ss command gather its data for ports etc

When trying to see port clashes within my system, many websites online recommend using /etc/services or ss -tunl to see port info I am noticing /etc/services is providing different information to -ss ...
Rachel1983's user avatar
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0 answers
59 views

Emulate ttyS0 on Ubuntu 22 or link it to ttyUSB0

I have a JAVA code that checks if ttyS0 is present. I dont have a serial port, so Im getting: Exception in thread "main" java.lang.RuntimeException: Error opening "/dev/ttyS0" ...
Aleksander's user avatar
6 votes
2 answers
2k views

Why is my LAN cable opening an UDP port on my computer?

OS: Debian 12 I'm working on my OPSEC pretty often because security is very important for me. Now I have a new router which opens a port on my computer when I plug in the LAN cable. When I disconnect ...
clooney's user avatar
  • 81
1 vote
0 answers
48 views

Find out what MAC addresses are connected to each physical LAN port of router

I'm managing a router running Linux 3.10.87-rt80-Cavium-Octeon On the router's GUI, there's a "Switch ports" page where I can see all ethernet ports (4 LAN - 2 WAN) and their corresponding ...
mariano-daniel's user avatar
0 votes
1 answer
31 views

Finding out all blocked port numbers

The Internet connection in my hostel room is provided by my college which blocks a few ports (eg. 6881-6889 to prevent usage of torrents). I want to find out exactly which ports are blocked, because I'...
Shubh Kumar's user avatar
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20 views

Port service translation

I have one public ip and only one inbound port to listen in my machine. How do I redirect port request based on client service? For example, my server is listening on 12345 (TCP/UDP) with public ip 35....
Muhammad Ikhwan Perwira's user avatar
6 votes
2 answers
1k views

Given a service name, get its port number?

Hi I feel like this is an obvious question but I haven't been able to get a good answer so far. Given the name of the service (which I know running on localhost) is there any networking command line ...
First User's user avatar
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1 answer
93 views

I can't block a port with ufw

This morning I received a report from Netscan: Netscan detected from host 8X.19X.1X.1XX time protocol src_ip src_port dest_ip dest_port Fri Sep 15 05:21:59 2023 UDP 8X.19X.1X.1XX 5065 => 9.87.179....
Willy Makend's user avatar
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51 views

Ubuntu Virtual Machine not detecting Arduino, it yields "Can't attach the USB"

I am facing an issue when I try to detect the Arduino on the Virtual Machine which is running Ubuntu 20.04. When I connect Arduino on my Laptop (Macbook), the Arduino IDE on the Mac detects the ...
Inderjeet's user avatar
0 votes
2 answers
434 views

Does firefox using port 80 / How to stop it

Everytimes I open my pc and try $ lsof -i :80 I get COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME firefox 3082 totoXXX 41u IPv4 100396 0t0 TCP totoXXX-PC-E15-Gen-2:39000->...
Cutis's user avatar
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1 answer
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Why does netstat show my socket tutorial program having a port of "x11-1" instead of the port I set in code?

I am trying to learn about socket programming, and I have the following function to set up a socket: 29 int CreatePassiveSock(char *protocol, char *portstr, int qlen) { 30 ...
Anthony De Vellis's user avatar
0 votes
1 answer
446 views

"Can't connect to ('0.0.0.0', 80)" when asking Doccano to serve on port 80: what is the issue?

I use Doccano on Ubuntu 22.04. I get the error "Can't connect to ('0.0.0.0', 80)" when asking Doccano to serve on port 80: what is the issue? Asking Doccano to serve on port 8000 works fine....
Franck Dernoncourt's user avatar
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0 answers
351 views

What is "mtr --report --tcp --port=22" telling me?

RHEL 8.4 Here's the output of mtr to a server for which the firewall is open to port 22: $ mtr --report --tcp --port=22 --no-dns Server1 Start: 2023-08-09T21:49:20-0400 HOST: foo.example.com ...
RonJohn's user avatar
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1 vote
1 answer
764 views

How to safely open ports in ubuntu 22.04 for Cyber Protection Agent

In Ubuntu 22.04, I have installed the Backup Agent for Linux Servers "Cyber Protection Agent" on vps. I have followed this link https://www.ionos.com/help/server-cloud-infrastructure/cloud-...
hous's user avatar
  • 111
3 votes
2 answers
525 views

what is BHFHS protocol port 248?

I am pondering using port 249 for NFS RDMA in RHEL 8.8, using the NFS export secure option requiring the port be below 1024. https://www.iana.org/assignments/service-names-port-numbers/service-names-...
ron's user avatar
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2 votes
3 answers
2k views

NFS4, insecure, port number, rdma contradiction help

With RHEL 8.8 currently, and RHEL 9.x, the latest NFS version is 4.2. When NFS 4 was introduced, it did away with a few things in NFS3 one of which was multiple port numbers: NFS4 mandates all ...
ron's user avatar
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0 answers
32 views

Netcat uploads hanging after a certain point

I'm working through an introductory cybersec challenge that requires me to upload a word and brute force a 4 digit code to a port. I put the combinations in a file, and tried to use netcat to upload ...
Noah Massey's user avatar
0 votes
1 answer
502 views

Curl always trying to connect with http in home network

Tldr; From my home network on a (MacOS Venture 13.4): curl https://ifconfig.me works but curl ifconfig.me or curl http://ifconfig.me not working. When connecting to other networks both work fine. Is ...
Anand Prem's user avatar
0 votes
1 answer
499 views

Understanding dsi system in device tree

Let's say there is a video bridge like sn65dsi86. It has a driver ti-sn65dsi86.c in kernel source tree. It should be enabled with device trees. There an example for device tree. But it is not complete....
ptiza_v_nebe's user avatar
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0 answers
77 views

Nmap scans are not persistent after reboot

I use Zenmap on Linux 6.0.0-kali3-amd64 which runs on Oracle VirtualBox to see open ports in Metasploitable2. When I save the Zenmap scan to /home I can successfully open the scan again until I reboot ...
Aditya Khare's user avatar
0 votes
1 answer
86 views

TCP port visible from inside nor outside

I've used autossh (reverse) connecting to my server. The ssh side works like used to. But in an ARM64 system, my Ubuntu has less possibilities but this is another story (...). So what I see whit nmap ...
Erkman's user avatar
  • 3
1 vote
1 answer
8k views

Telnet connection refused

I have been trying to connect using telnet. I keep on getting Connection refused. After checking ports listening, I observed the port is listening to the localhost IP 127.0.0.1 but I wanted it to ...
James Emeka's user avatar
0 votes
1 answer
241 views

limit connections per port

My question is about setting a connection limit to each port. I've made a v2ray server for VPN using x-ui. When I create a new config for users, each config uses to a random port. Now I want to limit ...
Mohammad javad's user avatar
-1 votes
1 answer
259 views

How can I forward port 8080 from my linux machine to be visible on port 2007 of my internal network using ssh?

I have a linux server hosting an applcation on port 8080 Inside putty, i have create a port forward from port 2007 to 8080 by specifying the public IP of my server, where's covered in red below How ...
melki0795's user avatar
2 votes
0 answers
828 views

Which systemd service this port use?

I have installed a program that uses systemd sudo netstat -lntp | grep 10700 tcp 0 0 127.0.0.1:10700 0.0.0.0:* LISTEN 2444/systemd tcp6 0 0 ...
Kokizzu's user avatar
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0 votes
2 answers
96 views

Is not possible change MySQL's port at Fedora Server 36

For Fedora Server 36 was installed MySQL 8 Community through the .rpm from MySQL Community Downloads. Now according with the Editing Conf. Files section is indicated to use the /etc/my.cnf.d/community-...
Manuel Jordan's user avatar
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0 answers
786 views

Ubuntu Server can't Access the apache outside localhost

I know this question is already posted alot but I already read them all and not solve my problem. I already have fresh install ubuntu 20.04 with fresh installed mysql,phpmyadmin,apache when i open my ...
Ace's user avatar
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0 votes
1 answer
33 views

Open port on Ubuntu Dektop not accessible out of machine

I have opened 9591 port with 0 0.0.0.0:9591 on Ubuntu Dektop machine, $ netstat -tulpn | grep 9591 (Not all processes could be identified, non-owned process info will not be shown, you would have to ...
Vishwadeep Singh's user avatar
1 vote
1 answer
1k views

Ports not reachable after reboot

after I rebooted my server, I can no longer ssh into it. I am running headless Ubuntu 20.04.5 After investigating the problem, I've noticed, that all ports on my server appear to be closed (using an ...
maddes's user avatar
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1 vote
0 answers
121 views

Server hosted on virtual machine with VPN can't be accessed on host machine using same VPN?

I am an absolute novice so there may be misunderstandings etc. any and all forms of help are very appreciated. On a virtual machine (Virtual Box) using Kali Linux I am hosting BeEF with OpenVPN ...
bobbbb's user avatar
  • 11
0 votes
1 answer
485 views

Opening a "closed" port

I am trying to set up a SAP System on SUSE Enterprise, but I'm having trouble connecting to the server. I added multiple ports to the public section of the firewall and with most of them I am able to ...
smcks's user avatar
  • 1
2 votes
1 answer
398 views

Blocking a specific port

I need to block specific ports temporarily on AIX 7.2 to simulate an application using this port. I am developing a workaround for an application ignoring the entries in /etc/services and using ...
bakunin's user avatar
  • 531
1 vote
0 answers
172 views

SSH connection refused on external network with the default username

I recently tried to configure port fowarding on my raspberry pi, to be able to connect through it from anywhere. So, I changed my box parameters to permit it. It seems to work, as my raspberry pi is ...
Kyrela's user avatar
  • 41
1 vote
1 answer
653 views

is there any way to limit number of clients (IPs) to connect a port ? (ubuntu 22)

I'm trying to find a way to limit the number of IPs that can connect to a certain port. here is a simple example that returns the number of unique IPs connected to a port netstat -ntu | grep :80 | ...
AmirReza Azartoos's user avatar
0 votes
1 answer
285 views

UFW seems to be ignoring allowed ports in specific cases

I've got a Raspberry Pi set up with UFW firewall to try and secure it as best as possible. Most of the rules seem to work absolutely fine, but for some reason, it's blocking specific connections which ...
BallistiX09's user avatar
0 votes
1 answer
191 views

How do I expose a port that an app is only allowing local connections to?

An app on linux-based "headless-box-1" is listening for HTTP connections on http://127.0.0.1:7860. Which restricts connections to self. But I wish it was listening for connections from any ...
Benjamin H's user avatar
0 votes
0 answers
1k views

Enabling outbound traffic on all network ports

I am working on a network gateway implemented with a single board computer running Ubuntu (I can't confirm the version since it is not an off-the-shelf distro, it is built using buildroot). I am ...
WedaPashi's user avatar
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0 votes
1 answer
735 views

Disable port 8910 and then again enable when required in my linux based server

As you see below jsvc.exe is running on 8910 with PID 23943. [root@abc-163 ~]# netstat -tulpn | grep :8910 tcp6 0 0 :::8910 :::* LISTEN 23943/jsvc....
Sash_KP's user avatar
  • 111
0 votes
2 answers
5k views

docker exposed port not accessible from outside even when port is opened using iptables command

I have a sample docker tar image in my linux based server and ran that though docker run command as below where 9521f101839f is image id. docker run -p 0.0.0.0:9895:9898 -td 9521f101839f So now ...
Sash_KP's user avatar
  • 111
0 votes
1 answer
1k views

Socat specify source port

How do I specify source port in socat? In netcat I can simply: nc -u -s 192.168.0.1 -p 8888 192.168.0.2 9999 I tried socat udp4:192.168.0.2:9999 STDIN:192.168.0.1:8888 It's failed STDIN: wrong ...
Muhammad Ikhwan Perwira's user avatar
-2 votes
1 answer
593 views

How does a telegram bot work in Linux?

I wrote a simple telegram bot and it works great without conflicting with my firewall. But my question is this, in the firewall I have ports 80 and 443 allowed for my site, but when I write a TCP ...
Djon Doe's user avatar
1 vote
0 answers
1k views

Unable to connect to a listening tcp port 80, Iptables is not blocking it

I am trying to see if tcp port 80 is open on a debian 11 server. I logged into it using SSH and did curl -v telnet://localhost:80. It says connection refused. If I do the same with port 22, it shows ...
Cruise5's user avatar
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0 votes
0 answers
103 views

How can I make a port inside a virtual machine accessible to the host if the virtual interface has its traffic forwarded through a TPROXY target?

I have a virtual machine connected to virtual interface that has all its traffic sent through a TPROXY transparent proxy: ip tuntap add tap0 mode tap ip link set tap0 up ip addr add 10.0.0.1/24 dev ...
phantomcraft's user avatar
0 votes
2 answers
1k views

Check what service is running on a specific tcp/udp port

I'm looking for a command-line utility that allows me to check what service (eg: http/ftp/ssh) is running on a specific port of a remote machine. An example of how I imagine a program like this would ...
kess's user avatar
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