I try to access the apache server on another machine (Even at localhost). I used
wireshark to get the port number of the packets which are random port number vs 80. This is correct.
But at the mean time, I tried to print out the port number at in the kernel myself at ip_rcv() which tcph->source and tcph->dest. It turned out that these two port numbers are
also random.
Not sure what I am doing wrong, can anybody tell me where I can get the correct port number from kernel?
You can't get the port number from any kernel, to set the port number for a Linux web-server do the following if you have apache:
If you have Apache, then go to /etc/apache2/ports.conf and change the 80 to a desired number of your choice
Then restart your server with service apache2 restart
Then in the web browser of your choice go to http://SERVER-IP:portnumber
NOTE: If you change the port number from 80 you must enter the new port number after the url/IP.
Related
I have adjusted IIS to only bind to port 443. Yet when I go to HTTP (port 80) I get a 404 error which must be being returned by IIS. I expected "site cannot be reached". How do I accomplish this? It is throwing a vulnerability issue. I do not have any rewrite module in place.
Additionally when I telnet to port 80 on that machine I cannot connect (or it seems that way).
Even when I stop the w3svc service, I get a 404 response when I browse to the server.
Since it response 404 when you go to HTTP(port 80), it seems there is a service running with 80 port. So you can check it by steps below:
1. Open "cmd" and run the command netstat -ano, it will response a list of active connections.
2. Then find the item which use 80 port and record its "PID".
3. Continue to run the command tasklist|findstr {PID}, it will show the service which use 80 port. If you are sure this service is not important, you can stop it in "Task Manager".
Of course you can also use the solution provided by Lex Li.
Solution: It turns out ipv6 has got it's own firewall which I didn't know and it filtered out 80 and 443! Thanks so much Nicholas Pipitone!
I'm having difficulties to get apache to accept ipv6 connections (everything perfect on ipv4). Results from ready.chair6.net:
What I tested/tried:
Disabling firewall doesn't change the result
Getting apache to listen on all interfaces or specifically the ipv6 interface doesnt change the result
Executing 'curl https://v6.ident.me/' correctly sends me back my ipv6 address
Netstat tells me that both the ipv4 AND ipv6 address are listening for connections on 80 and 443
I'm really stuck here, what else can I do?
The MX record error means it's having a problem getting the IP address from the DNS servers.
Solution: Try dig +short AAAA $hostname and dig +short MX $hostname, with $hostname being your URL. If you don't see an IPv6 IP in the terminal, then you don't have DNS fully setup. If you just recently setup your URL, then wait a day for caches to be updated. If it's been a while, talk to who you bought the domain name from / who's responsible for making your URL point to your IP.
Note: MX is only for mail. If you don't want incoming mail / that's not what the problem is, then that test is testing something it doesn't have to test, and you can ignore it.
More possibilities: Is the hostname on line 4 the same as the host name on the second to last line? Try pinging that IPv6 address from line 4 on a different computer (Not on the same private network); what do you get?
If you get a response, try nmaping the IPv6 on another computer to see if port 80 is open to the public.
-If the nmap fails then try checking your port forwarding settings if you're behind a NAT. If you're not behind the NAT then something might be blocking the request in-between their computer and your computer (Very unlikely); you can try telnet'ing to port 80 remotely and see if you're getting the requests - because then it's just an apache issue.
-If nmap succeeded, then what do you get? Send an HTTP request over command line from the another computer and see if you get a response.
If pinging doesn't work, then you're just not connected to the internet (o.O), idk how to help with that. If pinging the IPv6 works but pinging the URL doesn't, then dig must not be showing anything and it's the DNS as mentioned previously. If dig does show something in that case, then I'm lost.
I open IE explorer & Chrome in my computer and type localhost:80 and I get the index page.
Here I think my machine's IP is same to both connections (IE explorer & Chrome) and ports are too (80).
Note: Source port will be different (as destination is same: localhost IP), this is my second question.
So how webserver (lets say apache) handles this port 80 connections without failing? Does it port forwarding? In OS level even I tried with addr re-use, port re-use parameters and it is all same we cannot make multiple connection with same IPs & ports.
Now, probably you have came up with a solution: although source ports and IPs are same, destination port is different in package: <protocol>, <src addr>, <src port>, <dest addr>, <dest port>.
A. I got 49483~50004 ports as you can see on image. How client knows which destination port (49483~50004) is bound by webserver? If it is random between 0 and 65355 the webserver always binds all ports, it is very resource consuming. How webservers avoid from this?
Look at this image: command prompt-> netstat
If this question is related with low level sources it is OK, I understand Embedded TCP/IP/UDP, Phy MAC communication and package structures.
You have this all back to front.
All the port numbers at the server are the same: 80. So the client only has to know port 80.
All the port numbers at the client are different: 49483-50004 etc. So there is no ambiguity in the connection, because the 4-tuple you mentioned is unique.
All http request by default call to servers in the port 80, because servers listen by default in that port. So you only give an IP or hostname and the web browser add the default port (80). You can give a custom port if you web server is listenning in another port (usually Tomcat listen by default in 8080) for example you call it in: http://www.youamazingweb.com:8080.
A good example is see the IP as the home and the port is the door where clients enter to consume some resource hosted in server.
The Apache webserver uses port 80 to listen for incoming requests and replies over port 80. Firefox uses port 80 to send requests to webservers and then listens on port 80 for the response from the webserver. I have run Apache and Firefox simultaneously before and am just wondering how two different programs can share the same port.
Each side of a TCP network connection is defined by a touple of (ipaddress, port #). When a packet leaves your system all it knows is that it needs to find ip address 192.168.1.1 and go the whoever has a socket bound to port 80.
A server socket is going to be defined by the address on which Apache is listening and port 80. The client socket open by Firefox will have the same ip address but a different randomly assign port number which you normally do not see.
You can see it using netstat or tcpview (Windows)
For example when I run netstat right now I see:
tcp4 0 0 x.x.x.x.62993 stackoverflow.co.https ESTABLISHED
where x.x.x.x is my laptops ip address and 62993 is the random port number assigned to my web browser.
Firefox isn't listening to port 80. It's making a request to a server port and handling the response.
I am a newbie with Apache. I am learning .. after the installation when I tried to start the service I got the following errors.
The Apache service named reported the following error:
Unable to open logs .
The Apache service named reported the following error:
no listening sockets available, shutting down .
The Apache service named reported the following error:
(OS 10048)Only one usage of each socket address (protocol/network address/port) is normally permitted. : make_sock: could not bind to address 0.0.0.0:80 .
The Apache service named reported the following error:
httpd.exe: Could not reliably determine the server's fully qualified domain name, using 192.168.1.6 for ServerName .
The following error usually means that some other program is listening on the HTTP port (80).
(OS 10048)Only one usage of each
socket address (protocol/network
address/port) is normally permitted. :
make_sock: could not bind to address
0.0.0.0:80 .
In my experience, IM (chat) clients like to connect to port 80.
From a command prompt, (cmd.exe) run the command:
netstat -an
See if there is a listener on port 80 (Look for a line that says:
TCP 0.0.0.0:80 0.0.0.0:0 LISTENING
=== ====
the important thing being TCP and 80. If you find something, you'll need to track it down using something like TcpView
If Skype is your problem and it seems it usually is, alter Skype's port usage.
Click on Tools in Skype,
click on Options,
click Advanced,
click Connections.
In Connection is the option to use another port, I use a high numbered port such as 65432, then un-click the alternative use of port 80 and 443.
Close and restart Skype.
modifying C:\Program Files\Apache Software Foundation\Apache2.2\conf\httpd sloved the problem.
If you had installation problems, note that you might experience some errors such “ no services installed ”
if Apache is trying to share port 80 with another web server or application, such as a locally installed
firewall application. To fix this, you can tell Apache to use a different port. Open your httpd.conf file
in the conf subdirectory ( C:\Program Files\Apache Software Foundation\Apache2.2\conf by
default) and locate the following lines:
# Listen: Allows you to bind Apache to specific IP addresses and/or
# ports, instead of the default. See also the < VirtualHost >
# directive.
#
# Change this to Listen on specific IP addresses as shown below to
# prevent Apache from glomming onto all bound IP addresses (0.0.0.0)
#
#Listen 12.34.56.78:80
Listen 80
Change the last line of this block to read:
Listen 8080
skype uses port 80, try logout and shut down the program...
now run apache
if you are using windows os and believe that skype is not the suspect, then you might want to check the task manager and check the "Show processes from all users" and make sure that there is NO entry for httpd.exe. Otherwise, end its process. That solves my problem.
Changing in the config file every occurrence of the path to apache (eg: "C:/Users/xxxx/Desktop/Apache Software Foundation/") to the new location (in case you shifted directory of apache installation by copy paste) solved my problem. Hope it helps you too..
Please note that, not only http port 80, may your ssl port 443 is being used by any other service or software.
I have installed vmware workstation on my PC, so a process which was initiated by Vmware Workstation was using ssl port 443.
In my case, it was vmware-hostd.exe which was utilizing ssl port 443.
Try shutting down vmware-hostd.exe or simply change your ssl-httpd.conf and modify Listen from 443 to 8080 or something else.
While choosing the port number please be sure that you don't enter any port which can be used by any other software on your PC.
just provide the listen address and port in httpd.conf file. that will not show IP related error as
Listen IP_ADDRESS:PORT
If you change port ( not port 80) then port conflict will not occur and server comes up.
Below blog may help you :-
http://apache2-4-9-webserver-installation.blogspot.com/2014/06/how-to-install-apache-http-server.html
Port 80 conflict. There are a number of well-known Windows programs which use
port 80:
IIS
The most likely culprit is Microsoft Internet Information Server. Stop the
service with the command from the command line on Windows 7/Vista:
net stop was /y
If needed start the services again with the command from the command line on
windows /Vista:
net start was /y