Port is a generic term that can refer to port number (software related term), and computer hardware port. Here, questions referencing this tag refer to port numbers.

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6
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1answer
1k views

Is it bad practice to run a web application server directly on port 80/443

I am hosting a web app on amazon aws, using an ec2 instance. On that instance i will be running only one application. using glassfish v3.0.1 I do not want to run the app using : ...
30
votes
1answer
51k views

What ports to open for mail server?

I have just finished setting up a Postfix mail server on a linux (ubuntu) platform. I have it sending and receiving email and it is not an open relay. It also supports secure smtp and imap. Now this ...
35
votes
4answers
19k views

Bind to ports less than 1024 without root access

I would like to run applications I'm working on that binds to port numbers less than 1000 without requiring root access. I'm using Linux Mint and have root access to set it up. I would ideally like ...
14
votes
1answer
10k views

nginx: no permission to bind port 8090 but it binds to 80 and 8080

I'm struggling with some strange permission related behavior: when I configure nginx to listen to port 8080 everything works as expected, but when I use any other port I get something like 2014/01/10 ...
11
votes
5answers
14k views

netstat shows a listening port with no pid but lsof does not

This question is similar to Network port open, but no process attached? I've tried everything from there, reviewed the logs, etc... and can't find anything. My netstat shows a TCP listening port and ...
37
votes
16answers
37k views

Why Block Port 22 Outbound?

I'm a programmer, and I have worked for a few clients whose networks block outgoing connections on port 22. Considering that programmers often need to use port 22 for ssh, this seems like a ...
21
votes
7answers
145k views

What firewall ports do I need to open when using FTPS?

I need to access an ftps server (vsftpd) on a vendor's site. The vendor has a firewall in front of the ftps server and I have a firewall in front of my ftps client. I understand that ports 990, 991 ...
50
votes
11answers
10k views

Does changing default port number actually increase security?

I have seen advice saying you should use different port numbers for private applications (e.g. intranet, private database, anything that no outsider will use). I am not entirely convinced that can ...
6
votes
2answers
20k views

Node.js is not accessible from external IPs on Ubuntu

Hey everyone, I'm sure this is very noobish, so forgive me. I'm trying to run a node.js server on port 8080 of my ubuntu 10.04. Here's the result of iptables -L on the server: Chain INPUT (policy ...
8
votes
3answers
4k views

Debian - Port 80 is blocked, but I don't know by what

I can't make lighttpd listen to port 80. ~# /etc/init.d/lighttpd start Starting web server: lighttpd2013-03-16 23:15:02: (network.c.379) can't bind to port: 80 Address already in use failed! ...
5
votes
5answers
5k views

Many ISP's is block port 25, how do I choose an alternative port?

I am building an application that will be acting as a combined MUA/MTA on different networks. However, many of the networks are with ISP's that block port 25 for SMTP. Therefore I would also like to ...
1
vote
1answer
2k views

How do you run Nginx on port 8080 and Apache on port 80 on the same box?

I want to install Node.js on my box (CentOS 5) for testing and sandboxing but I can't uninstall Apache as recommend by developers using Nginx. So what I'd like to do is have Nginx serving ...
60
votes
3answers
411k views

How to check if a port is blocked on a Windows machine?

On the Windows platform, what native options to I have to check if a port (3306, for example) on my local machine (as in localhost), is being blocked?
6
votes
3answers
12k views

How to assign a hostname to SSH tunnel

I'm using ssh root@my.server.ip -g -L 4321:localhost:28017 to establish a tunnel from my MacBook to my dedicated server at my hosting provider. It works well. Now I want to access several admin sites ...
7
votes
4answers
5k views

How to make a URL point to a Tomcat instance?

Sorry if this question makes no sense (no expert here), but I understand that tomcat listens to port 8080 and that url are usually addressed to 80. Is there a way to tell DNS that urls should point to ...
5
votes
3answers
3k views

How do high traffic sites service more than 65535 TCP connections?

If there is a limit on the number of ports one machine can have and a socket can only bind to an unused port number, how do servers experiencing extremely high amounts (more than the max port number) ...
5
votes
8answers
7k views

Used/blocked ports in Ubuntu

starting up Glassfish AS would tell me the port 4848 is blocked (or any port that I configure). But checking the ports are not used. There is no firewall. root@ubuntu:~/glassfishv3/glassfish/bin# ...
4
votes
6answers
11k views

Regular user using ports below 1024 [duplicate]

Is there a way on Linux (CentOS if that matters) to enable regular users to use ports below 1024? (open listening TCP socket on that port) Currently I understand that only root has privileges to use ...
5
votes
4answers
974 views

Why was the FTP protocol designed to use more than one port?

The question is in the title. The reason I wonder this is because I'm coding an tcp service and would like to explore some of the reasons as they may shed some light on my work.
2
votes
2answers
522 views

Restrict User Access to Certain Ports

This question is purely hypothetical. Is it possible to restrict which ports certain users may use for their processes? Say users1 gets ports 8000-8999 and user2 gets ports 9000-9999. I am running ...
1
vote
3answers
715 views

Server Firewall preventing sending of email [closed]

The firewall on my VPS appears to be preventing my site from sending email. It was working fine until the end of last month. My hosting provider (Webfusion) has been next to useless. I am able to ...
3
votes
4answers
171 views

Linking Domain Names to Port Numbers

I have a [game] server (CentOS) that has about 10 used ports. For one game in particular, I have 2 servers: a private one and a public one. The IP for them is the same, so to differentuate between ...
2
votes
1answer
1k views

Windows Server 2003 - Block port on localhost

We have a misbehaving daemon running on one of our Windows 2003 Servers. It telnets into localhost:5115 I have a feeling that if I can stop it from telnetting into localhost I can get it to fail ...
1
vote
3answers
902 views

Securing phpmyadmin: non-standard port + https

Trying to secure phpmyadmin, we already did the following: Cookie Auth login firewall off tcp port 3306. running on non-standard port Now we would like to implement https... but how could it work ...
1
vote
3answers
188 views

IP tables - changes not persisting

I've tried to open port 8605 on my server (used for socket connections) using: iptables -I INPUT 2 -s 0/0 -p tcp --dport 8605 -j ACCEPT However the change is not persisting, the port closes itself ...
0
votes
1answer
214 views

SQL server port is blocked on client machine

I have a client machine on which sql server is installed. This machine is using the internet though a proxy machine. On the proxy machine wingate is installed. I could not connect to the remote sql ...
0
votes
0answers
685 views

changing ssh port. Useful?

i will buy a dedicated server soon. I would like to know if changing the default port of ssh may be useful for security or it's completly useless. And if it's useful which ports range should I change ...
-2
votes
1answer
67 views

Need apache to proxy subdirectory to another service

I have a website running on Apache, at 192.168.1.90:80 for xxxxxxxxx.com I also have a reddit instance running at 192.168.1.90:8001 for reddit.local I have been trying to proxy the url ...
-2
votes
4answers
504 views

DNS record, paths and port [duplicate]

Possible Duplicate: How to use DNS to redirect domain to specific port on my web server I have a domain xyz.com and a web application running at http://AAA.BBB.CCC.DDD:8080/pcc. When the ...
50
votes
4answers
50k views

What firewall ports need to be open to allow access to external git repositories?

What firewall port(s) need to be open to allow access to external git repositories?
12
votes
3answers
45k views

Opening up port 8080 in CentOS

I'm new to opening up ports in CentOS. I need to open up tcp port 8080 and have installed/ran nmap to find it is not open already. I've been reading about the iptables command, I have v1.3.5 installed ...
17
votes
1answer
22k views

Declaring multiple ports for the same VirtualHosts

Declare multiple ports for the same VirtualHosts: SSLStrictSNIVHostCheck off # Apache setup which will listen for and accept SSL connections on port 443. Listen 443 # Listen for virtual host requests ...
17
votes
4answers
8k views

Change protocol associated with port in wireshark

I'm trying to monitor some web traffic using wireshark. Our web proxy is on port 9191. How can I get the wireshark view to treat port 9191 just like port 80 - ie as HTTP. Just using Decode_As on the ...
17
votes
9answers
124k views

Disable TeamViewer from “stealing” Port 80?

How can you disable TeamViewer from using/reserving port 80? I am certain in the previous version <v4.1.6 there used to be a radio button option in "options" which disabled it from needing it, but ...
11
votes
4answers
14k views

How to allow non-root user to listen on privileged port?

I want syslog to run as a non-root user on my linux box. That makes it impossible for it to bind to port 514 - because that's a privileged port. Is there any way I can grant non-admin user "foo" the ...
6
votes
4answers
14k views

How can I redirect a port number on Linux?

I have a Tomcat application running on my Linux machine on port 8080 (www.myapplication.com:8080/myapps). I want to redirect the Tomcat port :8080 to the default HTTP port of :80 so that the ...
6
votes
6answers
13k views

Determining PostgreSQL's port

I know that by default PostgreSQL listens on port 5432, but what is the command to actually determine PostgreSQL's port? Configuration: Ubuntu 9.10 with PostgreSQL 8.4
2
votes
2answers
2k views

socat connect-connect “proxy” two inbound TCP connections to expose a firewalled service?

I'm struggling a bit trying to see how to use socat (or a similar TCP port redirector) to expose a firewalled service on a PC. Here's the scenario: I have a server PC which will be acting as a ...
2
votes
4answers
18k views

FTP/SSL in passive mode with portrange, which ports has to be open on the firewall?

We have to use FTP over SSL on our server and use a portrange with 5 ports for the data connection. A firewall is between client and server. We have to know what we have to open at the firewall: port, ...
10
votes
1answer
15k views

Failed to connect to 127.0.0.1 port 80

I have running nginx server (doesn't matter which server): $ sudo netstat -tulpn | grep 80 tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 4268/nginx tcp6 0 0 :::80 ...
5
votes
12answers
4k views

nmap shows opened port but netstat doesn't

If I scan my server with nmap, it shows that 21 port is opened. But when I login into this server and run netstat, I see nothing. $ nmap -sT server Starting Nmap 4.76 ( http://nmap.org ) at ...
3
votes
4answers
11k views

outbound ports that are always open

What are some ports that can NEVER be blocked outbound in firewalls, as doing so will stop basic internet use? Some I can think of are: port 53 udp/tcp -- dns, blocking this will prevent users ...
2
votes
0answers
21k views

Cannot telnet to SQL Server on port 1433

I've been working solidly on this issue for the past three weeks. I cannot seem to find where the actual issue is. I just recently found this article on how to troubleshoot the connection. I made it ...
1
vote
1answer
2k views

Block SSH access from specific countries

I found this handy script online, and would like to modify it to only block SSH access but I don't know anything about iptables and Im afraid Ill kill my system as i have no physical access to it. ...
1
vote
2answers
487 views

Forward all traffic on a specific port depending on the domain to another port

Imagine I have 10 different domains. All these domains have an A record to a single IP Address. There are ten different services hosted on this one IP. Let's assume they listen from port :80 to :90. ...
1
vote
3answers
4k views

Debian Open port 81

I install lighttpd in one server using port 81. The problem is that the port is closed, and I don't know how to open the port. Regards, Pedro
0
votes
1answer
6k views

iptables for Windows to redirect traffic

I am currently testing my server traffic and would like to route all incoming+outgoing traffic so as to be picked up by Burpsuite for analysis. Ideally, all traffic from ports 80 and 443 should be ...
0
votes
4answers
3k views

What firewall rules should be used for a home based system [closed]

I'm just setting up a home wireless network with connection to the internet. The router has settings to configure the firewall rules. Currently it's set to INBOUND ALL ANY and OUTBOUND ALL ANY. ...
4
votes
2answers
12k views

Should I use TCP or UDP to run a web server

I have just installed Apache web server on my computer. I have managed to use it locally (I can open index.php from my computer using my web browser). But I would like to make my web site available ...
3
votes
1answer
4k views

OpenVPN port-share with apache 443/10443 not working

I configured openvpn (OpenVPN 2.1.0) and apache 2 ( to listen respectively on 443 and 10443 (with modssl). The two applications are listening well: tcp 0 0 x.x.x.x:10443 ...