In computer networking a port is a software construct serving as a communications endpoint in a computer's host OS.

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Samba open ports, not being filtered

nmap scan of my ubuntu computer, output when ran with -sV: 139/tcp open netbios-ssn Samba smbd 3.X (workgroup: MEDIAPC) 445/tcp open netbios-ssn Samba smbd 3.X (workgroup: ...
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1answer
62 views

Strange behavior of Nmap

I do port scanning with Nmap when HotSpot Shield VPN is running; and I am receiving strange result - when HotSpot Shield is running, Nmap tells me that all of the ports are open and when HotSpot is ...
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2answers
35 views

What is this weird localhost IP traffic on multiple ports in the 5400-5600 range?

I am encountering an issue I recently have seen in my Fedora 23 machine (latest updates). I am getting about 130 IP packets passed back and forth over the lo interface in one go, every 1 second (like ...
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2answers
126 views

What can I do about being heavily port scanned?

I have two devices connected wirelessly to my Linksys router while running Symantec Endpoint Protection on my computer. A few days ago I started using the internet by connecting the cable directly to ...
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0answers
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Why is the maximum port range 65535 in the TCP/IP Suite ? [migrated]

My doubt is that - a port is just logical, so why such restriction ? Why can't I have a port of 9924593 or something like that ?
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5answers
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Why do hackers scan for open ports?

So, whenever you hear of the mean little hackers who hack websites you hear of "port scanning". I understand what it is (looking for all open ports / services on a remote machine), however that begs ...
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1answer
201 views

Can the windows Remote Procedure Call subsystem be modified from the default without causing Windows 8/8.1/10 to break?

This is a question that personally as a security professional has bugged me for a long time. So, a default Windows installation, from XP up to 10, typically has a few services listening on the ...
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2answers
88 views

Determining Firewall settings (Ports, etc) for specific applications

How can we identify the network or network firewall requirements for a Desktop or Web application. Meaning what ports are required by the applications. How the Cloud and non Cloud networks communicate ...
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3answers
124 views

Why is UDP port scanning slower than TCP port scanning?

I can't seem to find an answer for this. Any suggestions?
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2answers
52 views

All ports are unfiltered

I'm currently studying a peneteration/hacking course. I am trying to use nmap against a target to find all the ports that are filtered. I thought if I used an ACK-scan nmap would give me all the ...
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39 views

Port scanning on server

My use case is to check open ports on multiple servers, so when I try: nmap -iL list.txt then nmap only scans for some particular ports whether they are open or closed, but when I try: namp -p ...
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2answers
4k views

Setup of Kali Linux for reverse shell connections over the internet

I am running Kali Linux as a VM on my Windows machine which is NAT'd behind my company network, if I wish to pen test a website for a client and believe that a reverse shell is possible, what is a ...
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2answers
51 views

Windows 10: telnet - Openwall GNU/*/Linux telnetd running on an open port normal?

I noticed my internet connection was acting a little strange (stuttering up abruptly seemingly randomly), so I thought I'd see what's using it using Zenmap. I ran "Intense scan" using the latest ...
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4answers
11k views

How to listen to all ports (UDP and TCP) or make them all appear open (linux)

I got an external Debian server. The problem is that my university campus doesn't allow connections to go outside when the port is different than TCP port 22, 80, 443, or UDP port 123. I tested them ...
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2answers
35 views

Why do ALGs restrict traffic on a given TCP port based on the protocol?

My understanding is that application level gateways restrict the traffic they proxy based on port and protocol - say HTTP over port 80 or MQTT over port 1883. Both types of traffic are using TCP as ...
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1answer
32 views

Multiple users sharing the same IP

I'm setting up a quite unusual proxy for a very specific niche case. I'm allocating (ip,port) addresses to users, from which they can send and receive UDP and TCP packets. e.g. say someone is ...
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4answers
82 views

Running SSH on a different port vs adding the port number to a password

So, a pretty typical piece of advice is to run SSH on a high port number, thus decreasing the chances of it being attacked. The thing I have always wondered about though is that it seems more secure ...
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1answer
844 views

Firewalk through a Firewall on our subnet

Having trouble firewalking. I am trying to determine all the open ports on my firewall/gateway. Here is my lab network diagram: (Skip to the bottom of the following explanation for a direct list of ...
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2answers
63 views

Nmap scan report with all port status

Is there a way to ask nmap to print the final scan report with the state of all ports tested and the reason? For example when the scan is launched with --reason : Nmap scan report for 127.0.0.1 ...
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1answer
412 views

What is the fastest way to scan all ports of a single machine

I am doing some research and I need a very quick way to scan for open ports on a single machine. To provide some context, I know that my machine will have a port open waiting for UDP packets for about ...
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1answer
49 views

How to perform an idle scan against a target using Nmap with a list of zombies? [closed]

I want to perform port scan against a target but the firewall at the target only allows traffic to the ports through certain IP address/machines. I tried to perform an idle scan in Nmap but it only ...
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2answers
116 views

How to scan for ports opened by TCP/UDP sockets with nmap or any other tool?

I'm new to nmap and I've been digging with it lately to scan some devices on the current LAN for ports opened by socket programs which are running. First I ran a simple UDP server on my machine on ...
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4answers
4k views

How do you deal with massive port scans?

This morning I was looking through firewall logs and saw there were about 500 packets marked as port scan. The scanning range was from 1000-1200 5000-5200. The IP address is 85.25.217.47 which seems ...
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137 views

DDoS Mitigation - Whitelist or Blacklist Incoming SOURCE Ports?

For a network offering webservices, I have had recommendations to blacklist a couple of common incoming DESTINATION ports, such as UDP 53, to combat the increasing load from DDoS. I'm wondering if it ...
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3answers
148 views

Risk of running services on ports >1024

In a Reddit thread on securing SSH access to a Raspberry Pi, one commenter recommended running SSH on a non-standard port of 8123. Another commenter had this to say on the matter: Don't change ...
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1answer
68 views

Open ports on router

I have a TP-Link TD W8970 modem/router. Just for fun i tried to perform a port scan on it. I found this: $ nmap -p 1-65535 -n 192.168.1.1 Starting Nmap 6.00 ( http://nmap.org ) at 2016-01-21 16:17 ...
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1answer
83 views

Opening remote MySQL database to office IP address at default MySQL port risks?

I read a few questions regarding this topic that were pretty informative, but still wanted to pose my particular case. My company wants to put our data in the MySQL tables we have through our web ...
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1answer
351 views

OSSEC, what is it telling me about port changes?

I've been diving into OSSEC for the last couple of months, but I feel unclear on one of it's alerts. I've provided the alert below. The main difference I see in previous output and current output is ...
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4answers
12k views

Router Ports open

What ports on my home router should be open, say if I'm only using it for browsing the internet. Right now these four are open, 23/tcp open telnet 53/tcp open domain 80/tcp open http ...
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2answers
82 views

Why does nmap remotely show when I have port 6969 open, but not others?

Specifically, I was running a node.js application on port 6969 which I thought was strictly local. I discovered this was not the case when I ran nmap <myip> from a different computer and found ...
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1answer
451 views

What do Msgsrvr and Scientia-ssdb do?

I'm having a task in a computer security class in school where I'm supposed to scan a host for open ports in order to find out what services are being run there. I have found out (among other things) ...
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1answer
48 views

Safely Experimenting With Sockets

I'm learning about TCP/IP and (Berkeley/UNIX) socket programming. Let's say I have two scenarios: 1) I write two programs in C, a client and a server, and bind them each to a non-well-known port on ...
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1answer
94 views

Exploring unknown service

I'm fairly new to network stuff and currently exploring a Wi-Fi radio device in my home network. In this process I noticed an open port. 58028/tcp open unknown 1 service unrecognized despite ...
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1answer
43 views

Little bit confusing with nmap scan

I started MySQL with this command service mysql start and it worked pretty well. So: Using the netstat command, I found 127.0.0.1:3306 was in listening state, this is the MySQL service. So I did a ...
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2answers
48 views

How do I scan my Routers Ports? [duplicate]

I recently scanned ports from within my LAN, but I recently read in order to determine whether Ports are open to the WAN I need to scan from outside the LAN, how do I do this?
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1answer
40 views

Resuming an interrupted nmap scan:

I need to: --resume <filename>: Resume an aborted interrupted scan. But I didn’t: -oN/-oX/-oS/-oG <file>: Output scan in normal, XML, s|<rIpt kIddi3, ...
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1answer
66 views

Static MAC address on Switches and routers

I was having a discussion with a friend of mine in IS industry and he insisted that setting static MAC addresses (i.e. port security) on devices were a effective way to block MAC spoofing. I found ...
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2answers
157 views

How to limit source port for accessing blocked website?

My country has a firewall which blocks sites like Facebook, whatsApp etc. However, they use some kind of port blocking, so some important websites for me like Chegg is also getting blocked I think due ...
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1answer
150 views

Common attacks when no ports are open

If you have a web server with all ports closed (except, of course, the necessary HTTP) what kind of attacks can an attacker use to hack into the system? Are the only vulnerabilities stuff like ...
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1answer
93 views

FIN Scan: sneak through certain non-stateful firewalls?

Many resources stated that FIN scan can bypass non-stateful firewall: In Nmap document: The key advantage to these scan types is that they can sneak through certain non-stateful firewalls and ...
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1answer
115 views

What attacks or exploits are possible when MAC address, IP, and Port of a WiFi access point are known? [closed]

I just accepted a position at a small firm and was testing the previous WiFi setup for flaws and exploits that were possible. We have two AP's for business and guest connections, everything checks out ...
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2answers
1k views

Vulnerability of the open port

I'm installing service on the cloud machine and I was wondering on port vulnerabilities for my customers. My service which lives on server A (often on a customer site) needs to access server B ...
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1answer
4k views

Security risk of opening port 111 (rpcbind)?

As far as I understood rpcbind is used for listing active services, and telling the requesting client where to send the RPC request. If a host listens on port 111, one can use rpcinfo to get program ...
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2answers
55 views

nmap output to file different than interactive output?

I am running a simple SYN scan of all ports on all hosts that I found on a previous ping scan saved to a file: targets like this: nmap -sS -p- -v -T5 -oN puzzling.txt -iL targets As the scan runs ...
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1answer
128 views

Unable to open port on Windows 7 [closed]

The scenario is as follows: while a PC was connected to our company's network, a specific application was able to open another process on a predefined port. It worked as expected. But now, this PC ...
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2answers
421 views

Telnet port open on my router public IPv6 address

Recently I upgraded my home router into this one. It is a cheap one, but it has features I needed: IPv6 support and Gigabit Ethernet. So I decided to give IPv6 a try. I configured a Hurricane ...
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3answers
172 views

Does NAT really provide security? [duplicate]

I had an argument with someone on IRC about Network Address Translation. I was under the impression that NAT provided a layer of security to internal networks. I understand that's not the primary ...
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476 views

Does having these ports open indicate any vulnerabilities?

I installed Ubuntu Gnome a couple of weeks ago along with a few packages and some software. When I scanned my localhost using Nmap, I got the following results. Are there any obvious vulnerabilities, ...
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Is there any meaning in only allowing port 80 and 443 today?

It's become standard fare for security minded organisations to block everything other than 80 and 443. As a result, more and more applications (other than web browsers) are learning to use these ports ...
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1answer
62 views

Security concerns with opening ports [duplicate]

New to network security here. Is exploiting known/zero day vulnerabilities on "listening" services after scanning for open ports the only way or at least the most common way to compromise a system? ...