Questions tagged [port]
The port tag has no usage guidance.
178
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iptables: Failure when trying to block port access for most IP addresses, except for a few
I am using Debian 8 linux.
I'm trying to block input access to a few ports for most IP addresses, except for a small, select list of IP addresses. I am doing the following, but it does not seem to ...
- 271
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0
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32
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How to find port allocation? Bind for 0.0.0.0:80 failed: port is already allocated
My docker-compose.yml
version: "3"
services:
redis:
image: redis
restart: always
postgres:
image: postgres
environment:
POSTGRES_USER: user
POSTGRES_PASSWORD: ...
- 7
0
votes
1
answer
31
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Unable to get PID on a Listening port for Solaris
I'm using solaris
SunOS myhost4 5.11 11.4.42.117.3 sun4v sparc sun4v non-global-zone
I'm sure that port 7777 is in use as the telnet is successful as below:
$ telnet myhost4 7777
Trying 10.23.52.219.....
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0
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18
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How to debug source IP which try to access SSH server through port forwarding by SSH
my case is likely following case: SSH client(192.168.0.11) -> public cloud VM with SSH server and setup port forwarding (139.90.90.90)(CentOS7.9)-> one internal SSH server(10.24.24.24)(CentOS 7....
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1
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4
answers
84
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Can a NAT router run out of ports?
The highest TCP port number is 65535. If a router doing NAT uses an ephemeral port for each connection made to the internet on behalf of the hosts on the internal network, does this mean that it is ...
- 1,832
1
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0
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44
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Raspberry Pi 4 doesn't show USB camera as ttyUSB
I have an RPi camera and a USB camera connected to my RPi4.
lsusb:
pi@raspberrypi:~ $ lsusb
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 0c45:636b Microdia
...
- 111
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21
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lspci command doesn't detect monitor through mini dvi port
I just wired a just received 2005 Toshiba TDP S25 Projector VGA to the mini dvi port of my GP66 Leopard via an adapter. However, when I select "Computer 1" on the toshiba menu I have a mere &...
0
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1
answer
15
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Port is shown as "open", then as "filtered" on CentOS Stream 8
I have made a fresh install of CentOS Stream 8 on a machine. This machine needs to connect to a Foreman Smart Proxy on port 443.
If I run nmap immediately after machine boots up, it sees the port as ...
- 25.4k
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1
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19
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Nmap Shows Different States of the Same Port with Different Scan Methods
When I launch an -sA scan of a certain IP address, it shows port "80" as "unfiltered". Code is below.
sudo nmap -sA -vv -p 80 192.168.0.30 -Pn
Host discovery disabled (-Pn). All ...
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0
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88
views
Telnet error - "Connection timed out"
I am trying to telnet a port at a client's location.
telnet someexampledomain.com 25
It shows:
Trying someexampledomain.com...
telnet: connect to address someexampledomain.com: Connection timed out
...
- 101
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0
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35
views
How to limit web usage with nftables?
Between certain times, I would like to limit the amount of internet browsing I can do to force myself to focus (something like visiting ~3 sites per minute). This is what I came up with:
table inet ...
- 395
1
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0
answers
134
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Local port forwarding on Ubuntu 20.04?
I have a service listening on port :3000. However, I would like to change that to port :8080. Unfortunately, the program that I'm running does not allow me to change the listen port.
Is there any way ...
- 113
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1
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48
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Can two servers bind the same port?
I was surprised to discover that two servers I'm maintaining are both able to listen on port 3000 in development at the same time.
With the first server running, netstat shows
▶ sudo netstat -nap ...
- 103
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0
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27
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clearing port in use manually vs waiting 60 seconds
running lmgrd which is a license manager executable that comes with paid-for software, in a work environment.
I often resort to kill -9 <pid> of existing lmgrd processes found by doing ps -ef | ...
- 4,121
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176
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bash script, check port response with bash's built-in /dev/tcp, time delay | hangs | speed up
With this scripts i check if a host is response on a given port with the bash's built-in /dev/tcp.
I can use ip address or domains(hostnames).
Script 1
#!/bin/bash
HOST_NAME="127.1"
...
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0
answers
26
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How to drop packets to port 5901 other than localhost with nftables
I was trying to block VNC port 5901 from internet but accessible from localhost. I have a docker container running on the server, which works fine. After the following 2 commands, I still can access ...
- 1
1
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0
answers
27
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Docker expose port only to VPN
I'm setting up a DNS filter using Pi-Hole and OpenVPN on a VPS. Pi-hole is running in a Docker container and exposes port 80 for its web interface. How do I expose this port only to traffic ...
- 23
4
votes
1
answer
76
views
firewalld - where are the numeric firewall port numbers mapped to the service name?
# firewall-cmd --permanent --add-service=nfs
# filewall-cmd --permanent --add-service=rpc-bind
in RHEL/CentOS 7.9 if I do the above, what numeric port numbers are opened in the firewall?
Where is the ...
- 4,121
0
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0
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19
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Proxmox host - prevent port scanning outbound
I need some help to protect our /24 subnet to be abused by our customers which receives KVM instances with dedicated IPv4.
We would like to detect outbound port scanning activities and brute forcing ...
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0
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1
answer
149
views
ufw won't allow connections to postgres port 5432
With ufw disable on remote postgres system i'm able to connect from my local system
However, the connection does not work when I ufw enable as shown below:
C:\Users\HOME>telnet 80.240.24.195 5432
...
- 297
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0
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23
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Problem with server - client connection
I run PyCharm on a Debian 11.1 machine and I want to use the Remote debugging with the Python remote debug server configuration.
In this debugging procedure PyCharm emulates a server which connects to ...
-1
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1
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86
views
INVALID_PORT Error from firewall-cmd
When I try to add a port via
firewall-cmd --permanent --add-port=XXXXX/tcp
I get the error
Error: INVALID_PORT: XXXXX
Why?
- 1
0
votes
2
answers
235
views
How to receive a file and save it with socat
**** This is for learning purpose. I just like to deep dive into sockets, tcp, packets, etc.
For doing tests and learning, I began to "play" with socat
CONTEXT (tests) :
1- Bind a port to a ...
- 105
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0
answers
124
views
USB - usb2com device connect and disconect in Debian 11 (bullseye)
I am using Debian 11 (bullseye) a new installation at DELL T5610 workstation.
When connect an USB to COM port device it is recognized and mounted properly for a while and then it gone
Initial mount is ...
- 11
0
votes
1
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72
views
iptables/firewall-cmd DROP rules set last block ip rule set before
As follow is the list of the iptables rules that I have :
# firewall-cmd --direct --get-all-rules
ipv4 filter INPUT 0 -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
...
...
ipv4 filter INPUT ...
- 1
1
vote
1
answer
79
views
Stop Application from listening to a particular port
Background
We would like to configure a Linux machine so that it doesn't automatically listen to a port; whether a default port or not. We are using Oracle Linux and RHEL.
Issue
How can we prevent our ...
- 19
4
votes
1
answer
247
views
scp when both hosts are remote and use different ports
I am reposting a slightly edited version of this Ask Ubuntu question SCP with two different ports, as the answer there that works with command-line options only (without modifying ssh_config) no ...
- 485
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votes
1
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104
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Connection refused between 2 linux containers
On my host Ubuntu 18.04 I am running two lxc containers using default setups. Containers use Ubuntu 18.04 as well. I have an app running on container1 that offers an https based service on https://...
- 141
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0
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47
views
What is ftranhc service?
This the output of a nmap
$ sudo nmap 192.168.0.33
Starting Nmap 7.80 ( https://nmap.org ) at 2021-11-16 16:13 UTC
Nmap scan report for 192.168.0.33
Host is up (0.0062s latency).
Not shown: 997 closed ...
- 557
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135
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iptables Forwarding and port blocking
I have created the following Network in Virtual Box:
Linux Internal PC with 1 Static IP: 10.10.10.2
Linux Gateway/Firewall with 2 Static IP's and 1 NAT: 10.10.10.3 | 11.11.11.2 | NAT Network Card
...
0
votes
2
answers
95
views
Unable to connect telnet to mysql listen ip port from remote host
I m able to telnet locally to mysql process like below:
I have also made sure MySQL process is listening on all IPs by setting bind-address = 0.0.0.0 as evident below:
root@localhost:~# netstat -plutn ...
- 297
0
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41
views
Has my OS been hacked?
My phone has a malware that creates a virtual disk on the partition, so upon factory reset, it can continue is work. (I believe its a Chinese cryptojacking bug.. Runs a whole bunch of encrypted ...
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3
votes
1
answer
198
views
netcat closing connection on localhost listening end after connection attempt
Ι am nc-listening on localhost:2500
▶ nc -l 2500
_
On another terminal I am trying to connect to this listening end
▶ nc -zv localhost 2500
nc: connectx to localhost port 2500 (tcp) failed: ...
- 2,195
-1
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1
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222
views
What's the idiomatic way to allow incoming connections on a TCP port, as of 2021?
It's been years since I last fiddled with firewall rules; and I remember the iptables chains for input, forward and output, and their various rules. But the times, they have a-changed, and today ...
- 7,249
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0
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37
views
Does there exist an epheral port allocation service?
Following up on this question, it would seem that a server that allocates ports within a namespace would be an obvious and useful capability. One use case for such a service/server would be a ...
- 371
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1
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51
views
I have added port to firewalld but ECONNREFUSED will return every time I send a request
I'm working on Centos7 VPS and I have added port 9200 to firewalld, but I can not request this port and I will get this error Error: connect ECONNREFUSED from Postman.
My firewall status:
> ...
0
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0
answers
192
views
How to find USB device port in Linux?
I have a USB device connected to my computer, it is this one:
I want to use it in Python according to the example in this link. How do I know what to put for port (instead of 'COM1') in the line with ...
- 113
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1
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26
views
Get free/used ports in a specific range
Is it possible to get either the free or used ports between a specific range? If yes, whats is the command?
Thank you in advance!
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61
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list out all computer node connected to master node
I have HPC access, connected to other HPC via local IP or just simple hostname (i.e., compute1 or node3). I can log in to them by typing "ssh node3" or its IP like "ssh 10.2.6.20"
...
- 63
1
vote
1
answer
41
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Website served on port 80 unreachable from my phone in the local subnet
I'm building a website on my laptop. To see how it renders, I serve it locally on port 80 with lighttpd. I can then open it in my laptop's browser via any IP or URL referring to the laptop http://...
- 1,463
0
votes
0
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18
views
How to do Monitoring in a restricted network without Proxy
We want to monitor Customized Ubuntu 20.04 Kiosk Machines that run continuously in a very restricted Bank Network. For this, we tried to use CheckMK but that does not seem to work because of the ...
0
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0
answers
248
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On ubuntu 20.4, after starting Cassandra with systemctl, no process listens at port 7000/9042/7199
I installed a 3-nodes Cassandra cluster on three machines (all running Ubuntu 20.4) .
I could start either via systemctl start cassandra, or via cassandra -f command.
But I noticed that if I start via ...
13
votes
9
answers
3k
views
What's the point of firewalling outgoing connections?
I have a firewall (csf) that lets you to separately allow incoming and outgoing TCP ports. My question is, why would anyone want to have any outgoing ports closed?
I understand that by default you ...
- 697
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1
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145
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rhel + any best practice to minimize the CLOSE_WAIT sessions from linux side
when we perform the following cli on our rhel machine we get more then 600 CLOSE_WAIT lines
lsof -i tcp:8088 | grep CLOSE_WAIT
java 31100 yarn 385u IPv4 208022048 0t0 TCP master02.hgti.com:...
- 10.9k
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87
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how to know what the process that connected to my machine VIA specific port
with the following command I want to get which are the IP's that connected on my machine with port 8088
18.23.292.9 is machine that resource manager service is running on with port 8088
ss -tanp | ...
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1
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1
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984
views
Setting which ports to use for passive FTP connection with Linux's ftp client
I'm trying to connect to a FTP server behind a firewall that allows incoming connections in the range 6100-6200 only. I have successfully connected to this server using curl like this:
curl --ftp-port ...
- 697
0
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2
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35
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Is changing a service's port from one to another done by shells?
Some companies change the port address (number) of a service from one to another; for example, some companies change the address of SSH port from 22 to something else.
Is changing a service's port ...
2
votes
1
answer
122
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Non root user is not able to open any ports
I have an embedded Linux System built using Yocto. Just out of build, it only had a root user. I created a new user. This new user is not able to open any ports on the system even though they are ...
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184
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SSH RemoteForward port to remote Ubuntu is not working
My local machine is mac, I am connecting to a remote Ubuntu 20.04.2 LTS machine called mini.
Bellowing is the ~/.ssh/config section for mini
Host mini
User root
RemoteForward 8377 localhost:...
1
vote
2
answers
94
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How to make a port open?
When I ping, there is reply.
$ ping 10.26.14.16
64 bytes from 10.26.140.160: icmp_seq=1 ttl=63 time=0.525 ms
When I ping with port, there is no reply.
$ nmap -p 5016 10.26.14.16
5016/tcp closed ...
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