Questions tagged [port]
The port tag has no usage guidance.
57
questions
0
votes
0answers
13 views
With netcat how to safely open an external port to the Internet
I have found the perfect solution to write scripts which send files across machines over the Internet using netcat.
On the machine receiving files I do nc -l -p 1234 -k and then on the machines ...
1
vote
1answer
31 views
Why does SELinux (with Enforcing=1) allow binding to low (or any) ports, by default?
I assume that Selinux defaults, based on the documentation, mandate that basically all port operations would be blocked and logged as AVCs.
I have an SELinux enforcing enabled VM, created with ...
1
vote
0answers
31 views
Cannot change httpd listen port on anything other than 80 [closed]
EDIT: Nevermind, it was a selinux issue.
So I set up an apache server on an aws instance running rhel 7.6.
Whenever I change the listen port from /etc/httpd/conf/httpd.conf to anything other than 80,...
1
vote
0answers
17 views
Identify devices connected to the COM port in Ubuntu [duplicate]
I need to create an application that could identify the devices that are connected through the COM port of an Ubuntu system.
I've checked out a lot of codes and also tried to use them but I couldn't ...
1
vote
1answer
38 views
IPTABLES - Not able to open Ports
since i couldn't find anything that explains me what I am doing wrong I hope you guys can help.
I got a Ubuntu 18.04 server running. I want to open Port 9987 (just an example)
so i Tried to add it to ...
1
vote
3answers
60 views
KDE Connect Not Working [Ubuntu 16.04] : KDE Connect is not discovering phone and vice versa
I have installed the KDE Connect application on my desktop and on my phone [Xiaomi Redmi 3S Prime]. However the desktop application would not detect my phone and vice versa.
I have checked the ports. ...
1
vote
0answers
33 views
Cannot open/access ports on Ubuntu
I created an Apache web server on Ubuntu 18.04.2 LTS, using the guide described here. Afterwards the web server worked completely fine.
Later on I installed Libvirt onto the web server, after which ...
0
votes
0answers
14 views
Embedding in iframe web-application at a port on another application in the same server
I have an application at say port 5000 which can render embedded iframes.
https://host-public-ip:5000/
I have a second application on say port 6000. I would like to embed this page in an iframe in ...
0
votes
1answer
34 views
Understanding the Netcat properly [closed]
Netcat confuses me a little bit and here are the reasons:
when I run:
nmap localhost
There are some ports listed with the information whether they are open or closed. So if I run the command : nc -l -...
0
votes
1answer
23 views
SSH Tunneling, have some problems [closed]
I have a computer and host A, B. Host A has internet connection and host B placed in host's A local network. Host B has Web Interface at port 8080. I need to forward port on host A. And then i want to ...
0
votes
1answer
25 views
How to open a port to specific IPs in iptables while using docker?
I have a postgreSQL database inside of Docker that I don't want to expose it to the host network as it causes all users to see the exposed database port. (For now I don't have a pfsense or anything ...
0
votes
0answers
215 views
VSFTPD refuses to list directory when PASV is enabled
I'm configuring VSFTPD on Ubuntu 18.04 and have followed all the guidelines. It's working OK for plain FTP (insecure), however as soon as I enable SSL/TLS and Passive mode, it connects, but I am ...
0
votes
2answers
88 views
When does `[::]` or `0.0.0.0` mean this network and when this host? [duplicate]
Tanenbaum's Computer Networks says
The IP address 0.0.0.0, the lowest address, is used by hosts when they
are being booted. It means ‘‘this network’’ or ‘‘this host.’’
[::] is IPv6 version of ...
-2
votes
1answer
50 views
Does `rpcinfo` list the port number of a RPC service?
$ rpcinfo
program version netid address service owner
100000 4 tcp6 ::.0.111 portmapper superuser
100000 3 tcp6 ::.0.111 ...
1
vote
1answer
86 views
Why does postgresql server have a `localhost:57504` to `localhost:57504` UDP “connection”?
$ sudo netstat -ap | grep postg
tcp 0 0 localhost:postgresql 0.0.0.0:* LISTEN 1567/postgres
udp 0 0 localhost:57504 localhost:57504 ...
1
vote
1answer
46 views
Why is mysql server accepting nonlocal request, while postgresql server is not?
By default configurations, why is mysql server accepting nonlocal request, while postgresql server is not?
$ nmap -p0-65535 192.168.1.97
Starting Nmap 7.60 ( https://nmap.org ) at 2019-03-20 14:34 ...
0
votes
0answers
36 views
Why can't `lsof` report some open port's information? [duplicate]
I am running this with the IP address of the same machine:
$ nmap -p0-65535 192.168.1.198
Starting Nmap 7.60 ( https://nmap.org ) at 2019-03-20 10:13 EDT
Nmap scan report for olive.fios-router.home (...
0
votes
0answers
23 views
writing data out to already opened port
I have a setup in which one unix program (s51 from a microcontroller simulation package) is a server tied to a specific port. Let's call the port 111.
I also have setup a client on the same computer ...
2
votes
1answer
57 views
Red Hat Linux - port is in listening state but could not find process ID
I have this problem for my application, port is in listening state but process ID is not showing up. Used below commands. This is cloud AWS server Red Hat Linux.
$ netstat -tulpn
tcp 0 ...
0
votes
0answers
66 views
send hex as characters to output to remote end
I'm doing a project for a microcontroller that involves sending and receiving special (non-printable character) data through its serial port.
I found myself a simulator (ucsim) so I can test things ...
0
votes
1answer
36 views
Can't access SNMP stack on rasp pi through router from WAN
Background
I am running the following
On my laptop the very latest version of arch linux with all the latest updates. It is from this laptop that I am querying an SNMP stack on a rasp pi
$ uname -...
0
votes
2answers
220 views
Linux's Internet domain socket, transport protocols (TCP/UDP)'s socket and port
I have been bothered for a long while by some confusions among
internet domain socket provided by Linux,
transport protocols (TCP/UDP)'s socket and
transport protocols (TCP/UDP)'s port.
...
1
vote
0answers
91 views
Why there are 65535 ports [closed]
Wondering why they chose to have 16-bit (65535) ports. Why not just 256 or millions. I understand it's a power of 2, but not why it was this size. Wondering in what situations it would make sense to ...
0
votes
0answers
16 views
Can't connect to OpenLDAP
i have installed iRedMail with OpenLDAP managing the Mail Accounts. So far that works. Now I wan't to connect other applications to that LDAP and I'm trying to use a LDAP Explorer "LDAP Admin" for ...
2
votes
1answer
39 views
Is there a way to figure out what physical port a drive is being inserted into through linux?
Without knowing the order of which drives are being inserted and which ports they are being inserted (by human eye), is there a way to tell where they are being inserted using linux commands? I need ...
0
votes
1answer
51 views
Open port 4000 for Trader Workstation in Fedora
I have installed Trader WorkStation by Interactive Brokers. However, the program does not run, with assistance from support I found that the firewall is the problem.
The servers (several primary and ...
0
votes
0answers
14 views
OpenVPN Gateway with Killswitch and Prerouting Ports
My Prerouting in UFW Doesnt work. I´m using an VPN Connection via tun0.
Internet Connections via tun0 as a gateway works but not the Port Forwarding.
im on debian Strech 9
UFW Before Rules. Only ...
0
votes
1answer
296 views
iptables priority
After deploying all kubernetes ressources I wanna open port 443. I added it to my whitelist table but it is still closed. Same already happened to me for port 80. After flushing all tables, deleting ...
-2
votes
2answers
79 views
How make a port appear open with an nmap scan
To avoid someone knowing which port are open on my machine, I thought it would useful to open all unused port so that the nmaper is unable to identify which port are really open.
How make a port ...
0
votes
1answer
45 views
Networking: port listening but nc fails
I have set up a docker-compose stack on a server.
One of its services is jaeger collector and is configured as follows:
collector:
image: jaegertracing/jaeger-collector:1.8
environment:
...
0
votes
1answer
30 views
One port is listening with an * and the other is listening with 127.0.0.1 and only the first is accepting remote connections
Please see the attached picture below, and then I will explain:
So, I have Solr running which uses port 8983. And as you can see in the screen shot, it's listed as "TCP *:8983 (LISTEN)". And, it's ...
0
votes
2answers
131 views
port 1556 listening on tcp6 causing issues
on my RedHat 7, i noticed that network connection for Netbackup stopped working and i tried everything including rurning off my firewall and disabled SELINUX with no luck. the only thing i noticed ...
0
votes
1answer
90 views
How to close nc port in Debian 9?
I am struggling to close these ports which seem to be backdoors -- or at least I have never opened and used them. How can I close or shutdown nc and close these ports?
netstat -lntup | grep nc
ps-...
-1
votes
1answer
42 views
Restrict inbound access on localhost:TCP port
For reasons beyond my control, I have a binary that binds to TCP "localhost:$PORT". (Unix socket bindings would make this question moot).
If I understand correctly, this means that although no ...
0
votes
1answer
41 views
Blocking ports with iptables 1.4.2
I am trying to block some ports on an embeded uClinux· The Iptables version is 1.4.2.
The command I used was
iptables -I INPUT -p tcp --dport 22 -j DROP
But it seems that iptables 1.4.2 is not ...
0
votes
2answers
84 views
Telnet - how to verify why a port is blocked?
We have linux machines with RedHat 6.5 operating system.
When we try to telnet to localhost on port 8182, we get connection refused:
service iptables status
Firewall is not running
telnet localhost ...
0
votes
1answer
384 views
nginx: Can't bind to port (already in use) although no tasks running on that port [closed]
i just chose nginx for my webserver and I did follow this tutorial: https://github.com/groovemonkey/hands_on_linux-self_hosted_wordpress_for_linux_beginners
However, I just can't connect to my ...
0
votes
2answers
910 views
SSH Remote port forwarding with multiple ports
For those who worked with ssh port forwarding or for those who have an idea, I managed to create a remote tunnel from my PC to a remote machine(a camera that does not have a public address) through a ...
0
votes
2answers
194 views
iptables allow everything, is it safe?
The os is Ubuntu Server 18 and I am running a web server on it.
Is it safe to accept all traffic on all ports?
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
I tried ...
1
vote
2answers
5k views
How to check which localhost's ports are used on the terminal? [closed]
I'm working on the Linux Ubuntu terminal and I'm wondering how to check directly on terminal which localhost ports are used please ?
0
votes
1answer
103 views
Which ephemeral ports are used with raw sockets
Referring to How source ports get assigned, I do know, how the local port is determined. (=> Random free ephemeral port).
However, why does my raw socket using socket(AF_INET, SOCK_RAW, IPPROTO_TCP) ...
0
votes
2answers
782 views
systemd opens socket, service fails to bind to this socket
I am working on RedHat7.5.
I made a systemd socket (/etc/systemd/system/barfoo.socket):
[Unit]
Description=This is the barfoo socket
[Socket]
ListenStream=0.0.0.0:123
NoDelay=true
BindIPv6Only=both
...
2
votes
1answer
306 views
IPv4 and IPv6 sockets with same port
Is it possible to have a single process that would have two sockets, one using the AF_INET and one using the AF_INET6 families, while both being bound to the same port number, e.g. 20000?
If the IPv6 ...
0
votes
1answer
239 views
Chainging proxychains DNS port
I am using a proxychains on Kali with a DNSCrypt nameserver which operates on port 443. When I start proxychains it tries to connect to the DNS server on port 53 and it returns a timeout. How can I ...
0
votes
2answers
90 views
remap port 80 to 22
I would like to remap incoming requests on port 80 to port 22 and tried the following: sudo iptables -A PREROUTING -t nat -p tcp --dport 80 -j REDIRECT --to-ports 22 but still, ssh -i key user@host -p ...
1
vote
0answers
20 views
Regulating user-daemons from listening on unprivileged ports (preventing server spoofing)?
If I have a port >1024 but that I want to reserve to one executable how can I ensure that no other executable can open and listen to a socket on that port?
/usr/bin/foo_srv -p 8080
/usr/bin/bar_srv -...
-2
votes
1answer
40 views
How to change the port number for any service? [closed]
I know how to change the port number through the config file of sshd but I want to know how do you change any port number for any service without going into the sshd condfig file or for any service in ...
0
votes
3answers
1k views
Port open/listen but no associated process
In the output of nmap -p- localhost I get an unknown open tcp port, that's different at each reboot. How can I determine which process opened it and listens through it. I tried many of the usual tools ...
-1
votes
1answer
68 views
How to open up a tcp server compatible with tcpgoon
I have tcpgoon installed on one computer, provided that there is a direct VLAN connection, how do I create a TCP server on my second computer?
17
votes
5answers
4k views
How do I get only the PID, without any extra information, of a process running on port 3000?
I'm using CentOS 7. I want to get the PID (if one exists) of the process running on port 3000. I would like to get this PID for the purposes of saving it to a variable in a shell script. So far I ...
