-1
votes
2answers
149 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 ...
0
votes
1answer
114 views

Finding the firewall port that filters internet traffic [closed]

In my office, we have static IP's for each system. All the internet traffic from our systems are filtered with a Fortiguard firewall. Is it the default gateway where the firewall is installed? How can ...
1
vote
2answers
142 views

What security does an ISP provide for its customers?

I've heard that ISPs provide some kind of protection; using NAT and firewalls, to prevent hackers from using tools such as nmap to attack customers from over the Internet. What other technologies are ...
2
votes
3answers
416 views

Why block network ports?

There was another good question here on why you should block outgoing traffic: Why block outgoing network traffic with a firewall? But I was hoping to get an answer on why it is a good idea to block ...
2
votes
1answer
497 views

Why are some ports reported as closed by nmap?

I was scanning a machine from inside the same LAN which is running and up to date Windows XP Home Edition which I suspect may be running some malware. The target machine has an up to date antivirus ...
-1
votes
1answer
860 views

How to find IP Addresses that have been attacking my Computer Ports ? [closed]

I am a newbie at Info Sec, and wanted to know which IP addresses are sources of attack traffic. Can I also find out which ports are being attacked? Can this information be found in windows firewall? ...
2
votes
0answers
48 views

Could you attack a port without knowing what service was listening? [duplicate]

A lot of discussion I see suggests that changing default ports for services is just "security by obscurity" and is easily defeated by scanning for open ports. My question is this, though, if the ...
2
votes
3answers
3k views

Is it really better to use port 80 or 443 for outgoing traffic in order to bypass user firewall?

I recently created a reverse connection shell in C#. I tested it with some computers and I noticed that some computers connected back correctly and I established connection with them but another ...
5
votes
2answers
1k views

How should an outgoing connection white-list be created?

I see my previous question was closed as duplicate of Why block outgoing network traffic with a firewall?. The answers that everyone agree with mention the value of blocking outgoing connections (to ...
3
votes
2answers
2k views

If a port is closed how come you can still use it?

What does it actually mean for a port to be closed or stealthed? According to tests I've run all my ports (tested) are stealthed but clearly I can still use the internet. Also are the terms "blocked" ...
0
votes
2answers
296 views

can a backdoor executable be used on an occupied port?

Suppose I am doing a penetration test on a network that has a firewall that blocks all ports except 80, 110, and 443. I want to use a metasploit reverse-TCP backdoor executable written in msfpayload ...
1
vote
2answers
1k views

How to check if a port can be accessed from the outside

I want to be sure that the firewall protecting the intranet is effectively rejecting/granting access to a port. I have no access to the firewall nor any other external machine. Is that possible at ...
8
votes
2answers
2k views

ports blocked by firewall and not the server

I was asked this question at an interview and i wasn't sure about the answer. The question was "suppose you were checking the open ports on a particular webserver which was behind a firewall, how ...
17
votes
4answers
5k views

Dangers of opening up a wide range of ports? (mosh)

Why do we generally configure firewalls to filter out all traffic that we don't specifically allow? Is this just an extra layer of security for defense-in-depth that buys us nothing if we are not ...
3
votes
3answers
2k views

Which of these ports are safe to leave open, which are not?

I just ran nMap against my IP address and got the following result: PORT STATE SERVICE 21/tcp open ftp 22/tcp open ssh 23/tcp open telnet 80/tcp open http 443/tcp open https ...
3
votes
1answer
2k views

Is opening both TCP/UDP less secured than just TCP or UDP when needed and why?

If application needs opened port X UDP, or X TCP combination. Is there any potential risk by opening both UDP/TCP as I usually am not sure which one the application uses?
7
votes
3answers
6k 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 ...