Error Binding Socket To Interface Address Already In Use
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Bind Address Already In Use Linux
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Bind Failed Address Already In Use Iperf
takes a minute: Sign up Error: Address already in use while binding socket with address but the port number is shown free by `netstat` up vote 30 down vote favorite 8 I tried to bind my socket(server socket) at port address already in use socket number 8000. It worked and did the job for me. At the end of the code I close the socket as well. The very next instant I run my code again and it shows me that the address is already in use. I have printed the meaning of error values strerror(errno); to see if my code working properly at each point. To check if the port is free I checked it using netstat but it shows that port number 8000 is bind address already in use ssh free. It has happened with me a lot of times. Every time I then wait for a few more secs and then it starts working again. I am using c language. So what is he reason for this behavior by my OS. After a few more secs I run the code and then it works. anirudh@anirudh-Aspire-5920:~/Desktop/testing$ sudo ./a.out Socket Creation: Success File open: Success Socket Bind: Address already in use Socket Listen: Address already in use ^C anirudh@anirudh-Aspire-5920:~/Desktop/testing$ sudo netstat -lntp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:80 0.0.0.0:* LISTEN 1348/lighttpd tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 984/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1131/cupsd tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 1211/mysqld tcp6 0 0 :::22 :::* LISTEN 984/sshd tcp6 0 0 ::1:631 :::* LISTEN 1131/cupsd anirudh@anirudh-Aspire-5920:~/Desktop/testing$ sudo ./a.out Socket Creation: Success File open: Success Socket Bind: Address already in use Socket Listen: Address already in use ^C anirudh@anirudh-Aspire-5920:~/Desktop/testing$ c linux sockets share|improve this question edited Dec 18 '15 at 20:40 iharob 39.4k42851 asked Feb 24 '11 at 15:25 Durin 68731227 add a comment| 5 Answers 5 active oldest votes up vote 34 down vote accepted I've run into that same issue as well. It's because you're closing your connection to the socket, but not the socket itself. The socket can enter a TIME_WAIT state (to ensure all data has been transmitted, TCP guarantees delivery if possible) and ta
and both ends must ACK (acknowledge) each other's FIN packets. The FIN packets are initiated by the application performing a close(), a shutdown(), or an
Address Already In Use Python
exit(). The ACKs are handled by the kernel after the close() has completed. bind: address already in use mac Because of this, it is possible for the process to complete before the kernel has released the associated network resource,
Describe How Bind Function Works.
and this port cannot be bound to another process until the kernel has decided that it is done. Figure 1 Figure 1 shows all of the possible states that can occur during a http://stackoverflow.com/questions/5106674/error-address-already-in-use-while-binding-socket-with-address-but-the-port-num normal closure, depending on the order in which things happen. Note that if you initiate closure, there is a TIME_WAIT state that is absent from the other side. This TIME_WAIT is necessary in case the ACK you sent wasn't received, or in case spurious packets show up for other reasons. I'm really not sure why this state isn't necessary on the other side, when the remote end http://hea-www.harvard.edu/~fine/Tech/addrinuse.html initiates closure, but this is definitely the case. TIME_WAIT is the state that typically ties up the port for several minutes after the process has completed. The length of the associated timeout varies on different operating systems, and may be dynamic on some operating systems, however typical values are in the range of one to four minutes. If both ends send a FIN before either end receives it, both ends will have to go through TIME_WAIT. Normal Closure of Listen Sockets A socket which is listening for connections can be closed immediately if there are no connections pending, and the state proceeds directly to CLOSED. If connections are pending however, FIN_WAIT_1 is entered, and a TIME_WAIT is inevitable. Note that it is impossible to completely guarantee a clean closure here. While you can check the connections using a select() call before closure, a tiny but real possibility exists that a connection could arrive after the select() but before the close(). Abnormal Closure If the remote application dies unexpectedly while the connection is established, the local end will have to initiate closure. In this case TIME_WAIT is unavoidable. If the remote end disappears due to a network failu
for this is that you have stopped your server, and then re-started it right away. The sockets that were used by the first incarnation of the server are still active. This is further explained in 2.7 Please explain the https://www.softlab.ntua.gr/facilities/documentation/unix/unix-socket-faq/unix-socket-faq-4.html TIME_WAIT state., and 2.5 How do I properly close a socket?. 4.2 Why don't my sockets close? When you issue the close() system call, you are closing your interface to the socket, not the socket itself. It is up to the kernel to close the socket. Sometimes, for really technical reasons, the socket is kept alive for a few minutes after you close it. It is normal, for example for the socket to go into a TIME_WAIT state, on the address already server side, for a few minutes. People have reported ranges from 20 seconds to 4 minutes to me. The official standard says that it should be 4 minutes. On my Linux system it is about 2 minutes. This is explained in great detail in 2.7 Please explain the TIME_WAIT state.. 4.3 How can I make my server a daemon? There are two approaches you can take here. The first is to use inetd to do all the hard work address already in for you. The second is to do all the hard work yourself. If you use inetd, you simply use stdin, stdout, or stderr for your socket. (These three are all created with dup() from the real socket) You can use these as you would a socket in your code. The inetd process will even close the socket for you when you are done. If you wish to write your own server, there is a detailed explanation in "Unix Network Programming" by Richard Stevens (see 1.5 Where can I get source code for the book [book title]?). I also picked up this posting from comp.unix.programmer, by Nikhil Nair ( nn201@cus.cam.ac.uk):
I worked all this lot out from the GNU C Library Manual (on-line documentation). Here's some code I wrote - you can adapt it as necessary: #include#include #include #include #include #include #include /* Global variables */ ... volatile sig_atomic_t keep_going = 1; /* controls program termination */ /* Function prototypes: */ ... void termination_handler (int signum); /* clean up before termination */ int main (void) { ... if (chdir (HOME_DIR)) /* change to directory containing data files */ { fprintf (stderr, "`%s': ", HOME_DIR); perror (NULL); exit (1); } /* Become a daemon: */ switch (fork ()) { case -1: /* can't fork */ perror ("fork()"); exit (3); case 0: /* child, process becomes a daemon: */ close (STDIN_FI