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

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2answers
64 views

Client misunderstanding nmap [on hold]

My client wants their public facing IP addresses to be secure, but thinks that running nmap port scans will draw attention from hackers. To settle this once and for all, what do you say?
0
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0answers
16 views

Firewall issues

Background I have an Android device (Minix M5) that I handed to a customer The device only does outbound connections, so no inbound traffic The customer confirmed that s/he opened up the ports ...
1
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1answer
52 views

explanation of an nmap behaviour

I'm testing some vulnerabilities on a machine which has the port 22333 opened (it's used as the ssh port, and I can connect to it without any problem and the telned command get connected): $ telnet ...
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votes
1answer
41 views

how can the hacker benefit from the information of checking tcp port or udp port? [closed]

I studying a scanning and I want to ask how can the hacker benefit from the information of checking tcp port or udp port?
1
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1answer
41 views

Port forwarding with VPN

EDIT: My VPN has port forwarded a 5-digit tcp/udp port for me. What kind of attacks am I opening the computer to with VPN port forwarding?
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votes
2answers
211 views

What's the risk of opening ports 1-65535? [closed]

Just going to say this right now; this seems absolutely ludicrous. I've had a problem with playing Super Smash Bros. on Wii U ("Cannot connect to partner's device."; also happens for all ...
0
votes
1answer
68 views

Why is Parallels Plesk running on port 8443 > 1023?

Parallels Plesk, a server administration software package, uses HTTP(S) on port 8443 (ref). I know that ports <1024 are only available for root. This means that if the server Plesk is using for ...
1
vote
2answers
55 views

How do I check for inside-out open port? [closed]

I'm inside a corporate network and I want to assess which ports are open for outbound connection. There are such tools that do this test? I remember that years ago I used a website which performed ...
0
votes
1answer
72 views

Source port and destination port [closed]

Just fiddling with wireshark and telegram as part of some learning exercise on security. I realised that the source port for the telegram app is 58939 and the destination port would be 443. Why is ...
4
votes
1answer
167 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 ...
0
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2answers
162 views

Opening port 53 on server Risks?

I looked about but couldn't find a similar enough question. I have some remote servers positioned on clients networks, which provide various services (raspberry pi) - and their firewall config is as ...
1
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1answer
131 views

nmap not running as root shows unknown open ports for a fraction of a second

On a server running Ubuntu 14.04.2 I was doing some basic security auditing when I ran the command nmap -p -d 1-65535 as a non-root user. Interestingly it reported a few (1-5 at a time, average, ...
5
votes
2answers
790 views

Why would a stealth scan attract more attention than a connect scan?

I'm reading an Information Security book and am faced with the question: Why may nmap stealth scans(SYN) attract more attention than simple connect scans(TCP connect())? Why might it be?
1
vote
0answers
131 views

open ports on a netgear N-150 router; disable SPI firewall? [closed]

How do I open all ports? At least internally, for LAN traffic from 192.168.1.x to 192.168.1.x I want all ports open. Even if it creates a security problem. thufir@doge:~$ thufir@doge:~$ nmap -p ...
1
vote
2answers
94 views

Mitigating DDoS With Command of Ports

Is there any type of DDoS where closing or taking full control of all port capabilities would be useful in mitigation of an attack?
1
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0answers
711 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 ...
1
vote
1answer
114 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 ...
-4
votes
1answer
86 views

How am I affected by malware? Malware transferred from service provider's base station or just port scan? [closed]

I need a malware expert here. I am being targeted by advanced hackers over the 4.5 years. So this is my situation: 1) My new phone: I just bought a new phone, with SIM card and mobile internet plan ...
10
votes
1answer
6k views

GHOST: which services are vulnerable, ssh, web server?

GHOST (CVE-2015-0235) just popped up. GHOST bug: is there a simple way to test if my system is secure? deals with how to find out if your system is vulnerable. exim is mentioned specifically. ...
13
votes
2answers
1k views

What's the diff between blocking a port with a firewall and not starting a service on that port in the first place?

I was considering setting up a software firewall (pf) on my web server and did some research on them. Were I to do it, it'd involve basically blocking connections to all ports except 80, 443, and the ...
3
votes
4answers
664 views

Is there a nmap command to get the top # most common ports?

I understand nmap by default scans the top 1k 'most common' ports (-F reduces to 100) I understand it gets these 'most common' ports based on the nmap-services file, specifically the frequency (3rd ...
2
votes
1answer
125 views

Understanding nmap output / author explanation …(Scapy)

I just read this example and explanation (below) in the OReilly book Security Power Tools (2007) in section 6.3 that is written by the creator of Scapy, Philippe Biondi. I think the example is very ...
2
votes
1answer
349 views

Firewall and Torrent

I use my university internet network and all incoming connection is blocked on every port.(they use netasq firewall) They have no other restrictions which stops me from using a torrent client. Using ...
1
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1answer
144 views

Why is nmap that slow on my system (ubuntu 14.04)?

I just started to learn something about portscanning with nmap. when i try to run an a nullscan or any other type on a virtual machine (win7 no firewall) the scan needs a lot of time to perform: ...
32
votes
4answers
6k views

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 ...
0
votes
2answers
116 views

Only HTTP(S) port is open. Why do I need to worry about unpatched software?

Unpatched software poses no risk by themselves. They're only problematic when someone exploits it. How could malware get into my system if I do have unpatched software in general and I'm connected to ...
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votes
2answers
388 views

Which all ports are in danger and needs to be closed with immediate attention?

This is the nmap scan results on my server (used for email and web serving) from a remote scan. Which all ports are in danger and why? PORT STATE SERVICE 21/tcp open ftp 25/tcp open ...
2
votes
2answers
438 views

How to force nmap to check all the ports?

I heard that nmap scans for only 1000 most common ports while we do server scan. Is it possible to force nmap to check all the ports for scanning? If yes,How?
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2answers
142 views

What is the safest way to ssh to a machine behind a router?

I am thinking about forwarding port 22, to 22 on the machine behind router, but is it safe? Anyone can try to connect to my public IP on port 22 and then indefinitely try to guess user and password. ...
1
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3answers
70 views

What Mechanisms Keep Network Processes (and Applications) Sandboxed

This question stems from my other question, sorry if it is too similar. Now I would like to know what mechanism is used to sandbox network processes and (if relevant) individual programs, if at all? ...
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votes
1answer
173 views

Telnet Open, is this an exploit? [closed]

I am pentesting a server, and it appears my ports are open for telnet. Upon accessing telnet, if I type "help" I only get these commands: telnet> help Commands may be abbreviated. Commands are: ...
0
votes
1answer
221 views

Are these port secured on my AP?

I'm doing a project for my high-school and I'm trying to get the best security for my network. I've made almost everything in my access-point configuration and I have only 3 tcp/ports open on my AP: ...
2
votes
2answers
170 views

Protecting against GCHQ port scans: How does TCP stealth work?

Today I read the first time about a draft of TCP Stealth which should serve as a protection against GCHQ and NSA vulnerability scanning(Source: https://en.wikipedia.org/wiki/TCP_Stealth): The ...
7
votes
2answers
524 views

How nmap guesses the operating system?

nmap has the capability to guess the operating system with the option -O. I was highly surprised that it can find the correct kernel or service pack. * How nmap guesses the operating system? * What ...
0
votes
2answers
93 views

Impossible to make connections through closed ports?

If you have closed all your ports on your internet protocol, you cannot make a connection to that internet protocol. So how do attackers (DoS or any other means that need a connection) make a ...
3
votes
1answer
208 views

Internal IP addresses allowed access to all DMZ hosts

Hi basically I'm doing a vulnerability assessment for at the moment. The setup includes a DMZ with a single firewall and an internal network (3 legged network model employing a single DMZ) but on the ...
0
votes
2answers
274 views

Does Nmap requires a closed TCP port to do OS fingerprinting?

I was checking the security of a server by running Nmap. Last time it gives me the following results, indicating that OS could not be fingerprinted: PORT STATE SERVICE VERSION 21/tcp ...
3
votes
2answers
180 views

How common is port-knocking? [closed]

Today I read about port-knocking for the first time. It has been a pretty known concept for more than ten years, but I don't know anybody who uses it for their servers. How common is the usage of ...
0
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0answers
175 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 ...
0
votes
1answer
129 views

Detecting port scans in OSX kernel

Is it possible to detect port scans on OSX at the kernel level? I would like to write a kext that detects the ip addresses of systems scanning my computers ports. How exactly does a stealth scan ...
0
votes
1answer
98 views

Web browser initiating connection on non-standard ports. Should it be blocked?

I am doing some egress monitoring on my computer. Once in every few days, I would find some strange connections being logged, which I believe is initiated by the web browser through a related but not ...
1
vote
1answer
238 views

How to check whether firewall allows traffic on specific port but not listening on the port [closed]

I have client / server and there is a firewall between them.The server is listening on a port and I want to check if this port is allowed by the firewall. I can only know the ports that the machine ...
2
votes
2answers
960 views

I ran a netstat on my server and port 80 is listening, does that mean it is open and vulnerable to attacks? [closed]

Sorry I am just getting into Web Development and trying to learn more about servers and PHP, so I downloaded the LAMP stack on an Ubuntu14 OS and started an apache2 server. tcp6 0 0 :::80 ...
0
votes
2answers
66 views

Only allow access to specific service running on computer in Demilitarized Zone over internet

If a computer (running different services such as ftp and ssh) is placed on a Demilitarized Zone, will all of its services automatically be accessed by anyone on the internet? If the answer is yes, ...
3
votes
1answer
104 views

Is it possible to find out what a remote user is trying to do connecting to a closed port?

From my iptables log, I can observe a particular remote IP address trying to connect to my server from port 80 to a private port number: Jul 09 01:24:41 example.com kernel: IPTABLES: IN=eth1 ...
0
votes
1answer
132 views

How to turn of telnet and FTP on Thomson 789vn router? [closed]

I have run a port scan against a Thomson 789vn router and have noticed to my surprise that its HTTP as well as telnet and FTP ports are open. How can one turn off telnet (also FTP) using the router's ...
1
vote
2answers
236 views

Nmap stealth scan shows that port is filtered

The title is really bad, but I was able to find better. I have installed Debian on VMware, and set iptables to block any traffic except port 80 (inbound and outbound). When I run a nmap scan it shows ...
0
votes
1answer
140 views

NMAP not reporting open ports with -sS scan

Is there any reason why an -sS scan (or most others) would not report an open port that doesn't have a service attached to it? For example, in a regular -sS scan, the following port will be missing, ...
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votes
2answers
6k views

VPN blocked ports problem

I use VPN quite often in public places where I don't want anyone to read my web traffic. However, some public places have firewalls that block ports required to establish a VPN connection (I usually ...
3
votes
2answers
1k views

Is my ISP doing a port scan on my computer?

I have been logging incoming connections with iptables for a while and I have been observing the following popping up periodically: 11:45:10 my.com kernel: IPTABLES: SRC=220.255.XX.XXY ...