I am learning network prgramming in linux in c,and try to build a server and in this server I want to bind the listening socket to a paricular Ip address and port.Bind function is showing error,I did not want to use wild card. Here is the code.
#include<stdio.h>
#include<sys/socket.h>
#include<strings.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<string.h>
[Code]...
I am trying to create a socket to listen for a bootp response so I am using a PF_PACKET socket so that I get the response based on my mac. My problem is that I don't want to hear all traffic (as I do now) so would like to use a specific port number and bind to it.
View 1 Replies View Relatedis it possible using a perl script to test for a socket listening on a UDP port on a remote host ?I work in an environment where netcat is not allowed and from time to time I need to see if a UDP port is open on a remote host.
View 6 Replies View RelatedI am running vsftp on one of my systems and when trying to connect to it it errors out with this: vendion@Loki:~> ftp 192.168.1.100 Connected to 192.168.1.100. 500 OOPS: could not bind listening IPv6 socket
I have tried stopping the firewall and even disabling IPv6 nothing changed, any clues as to what is going on?
I am currently trying to get a B.A.T.M.A.N mesh network up and running. the thing uses UDP port 4305 for broadcasting to nearby nodes and it seems this port is closed or used by something else.
now i have tried to open this port with commands like
Code:
iptables -A INPUT -p udp --dport 4305 -j ACCEPT
iptables -A OUTPUT -p udp --dport 4305 -j ACCEPT
it still gives me the same error saying the socket cannot connect.any way for me to scan that udp port, see what is blocking it and open the thing up ?
If I open a raw SCTP socket, am I able to bind to a specific port? (I only want to see SCTP packets from a particular IP address AND port.) Or, any raw SCTP socket, regardless of port binding , will get all SCTP packets received by the OS from that IP address? The port doesn't matter and is ignored.
View 1 Replies View RelatedI make an application on GNU/Linux which listening on a MULTICAST stream, so I open my unconnected socket, bind it on a MULTICAST address and a port, join the multicast group with the "setsockopt (IP_ADD_MEMBERSHIP)", then I receive datagram on my socket.
Now I've two different instances of the same application that run with their own MULTICAST address and port. And what I found strange is that, after a misconfiguration, I switch the ports, for example:
Emitting on 225.0.0.1/23451 and 225.0.0.2/23452
Receiving on 225.0.0.1/23452 and 225.0.0.2/23451
And my receiving part doesn't care about the MULTICAST address, it looks like the socket is listening on the port number only! I mean that the receiver [225.0.0.1/23452] take its datagrams from emitter [225.0.0.2/23452] and vice-versa!
I finally got the certs to configure:
openvpn --config server.conf
Tue May 3 17:26:27 2011 OpenVPN 2.1.1 i686-redhat-linux-gnu [SSL] [LZO2] [EPOLL] [PKCS11] built on Jan 5 2010
Tue May 3 17:26:27 2011 NOTE: OpenVPN 2.1 requires '--script-security 2' or higher to call user-defined scripts or executables
Tue May 3 17:26:27 2011 Diffie-Hellman initialized with 1024 bit key
Tue May 3 17:26:27 2011 TLS-Auth MTU parms [ L:1542 D:138 EF:38 EB:0 ET:0 EL:0 ]
Tue May 3 17:26:27 2011 ROUTE default_gateway=192.168.122.1
Tue May 3 17:26:27 2011 TUN/TAP device tun0 opened
Tue May 3 17:26:27 2011 TUN/TAP TX queue length set to 100
Tue May 3 17:26:27 2011 /sbin/ip link set dev tun0 up mtu 1500
Tue May 3 17:26:27 2011 /sbin/ip addr add dev tun0 local 10.8.0.1 peer 10.8.0.2
Tue May 3 17:26:27 2011 /sbin/ip route add 10.8.0.0/24 via 10.8.0.2
Tue May 3 17:26:27 2011 Data Channel MTU parms [ L:1542 D:1450 EF:42 EB:135 ET:0 EL:0 AF:3/1 ]
Tue May 3 17:26:27 2011 Socket Buffers: R=[114688->131072] S=[114688->131072]
Tue May 3 17:26:27 2011 UDPv4 link local (bound): [undef]:1194
Tue May 3 17:26:27 2011 UDPv4 link remote: [undef]
Tue May 3 17:26:27 2011 MULTI: multi_init called, r=256 v=256
Tue May 3 17:26:27 2011 IFCONFIG POOL: base=10.8.0.4 size=62
Tue May 3 17:26:27 2011 IFCONFIG POOL LIST
Tue May 3 17:26:27 2011 Initialization Sequence Completed
But openvpn still won't start; where to go from here.
Tue May 3 17:54:25 2011 TCP/UDP: Socket bind failed on local address 192.168.122.3:1194: Address already in use
Tue May 3 17:54:25 2011 Exiting
How does bind system call names a socket.Code:bind(server_sockfd, (struct sockaddr *)&server_address, server_len);I see use of bind in majority of programms as above.But any of the arguments is not the name of socket.
View 1 Replies View RelatedI can't seem to get on my Twinkle SIP Phone, it says: "Failed to create a UDP Socket (SIP) on port 5060 Address already in use" after that message it brings me back to the window were I'm supposed to run my profile, how do I fix this?
View 6 Replies View Related- I setup port forwarding of openssh :
connect 1: ssh -g -f -p 11111 -i /<path-to-private-key> user1@ip-server1 -L 22222:ip-server1:161
- Then I setup second connection
connect 2: ssh -g -f -p 11111 -i /<path-to-private-key> user1@ip-server1 -L 22223:ip-server1:3306
- Openssh waring to me "bind: address already in use"
- So I think port 22223 have had another program use,I use command:
ps aux | grep ssh /* find process id of second connection */
kill -9 <process-id-second-connection>
netstat -an | grep 22223 /*find which program use port 22223> */
- but I can't find anywhat
- Then I run again command :
connect 2: ssh -g -f -p 11111 -i /<path-to-private-key> user1@ip-server1 -L 22223:ip-server1:3306
- And I receive a error from OpenSSH :" bind: address already in use"
In user mode [non-root] linux machine, tried to bind a socket by using a"ioctl(iInterfaceSocket, SIOCSIFADDR, &stCommand)". I am getting error 13 -> Permission denied because of user mode. If change from usermode to kernel mode everything works fine.I need to bind the socket in user mode only, please suggest solution for the abovewhile explaining the above,
View 2 Replies View RelatedI'm trying to add a key public key for my dev box which is a vm running ubuntu natty, and I am unable to connect via ssh. I've tried rsa and dsa, as well as these commands:
exec ssh-agent bash
ssh-add ~/.ssh/id_rsa
ssh-add ~/.ssh/id_dsa
[Code]...
I think I've found the error by running sudo /usr/sbin/sshd -Dd, but I'm not sure how to fix it:
ebug1: sshd version OpenSSH_5.8p1 Debian-1ubuntu3
debug1: read PEM private key done: type RSA
debug1: Checking blacklist file /usr/share/ssh/blacklist.RSA-2048
[Code]...
Is it possible to swap a client ip and port ? This is what I am trying to do. Let say you have Comp1 and Comp2 And you have Server between them. My goal is to get Comp1 and Comp2 know each others IP So Comp1 connects to server And server stores comp1's IP In a text file or other place And Comp2 connect to server And server also stores his info And then both comp1 and comp2 dowload the tex file And use the info on it.
View 9 Replies View RelatedI want to pass ip address,port address and some parameters from command line using python script.The ip address and port address for establishing socket connection and remaining parameters to execute different connection.
View 1 Replies View RelatedI am working with simple tcp client to establish connection to sockaddr_in servAddress and send data segment:
...
connect(sockfd,&servAddr,sizeof(servAddr)) < 0)
send(sockfd, pkt, pktLen, 0);
close(sockfd);
...
Elementary... Here's the tricky part: next i have to handle user level ack the server is sending to "client"... To do that i have to open server socket on the same port number the system assigned to my client socket before. How can i get it ( in user level code)?
I want to get the connected client MAC Address after accept() call. I can get the IP address of the client but i don't know how to get the client MAC Address in my this programme. Here I am Posting my Code.
#include<stdio.h>
#include<sys/socket.h>
#include<sys/types.h>
[code]....
I have a customer who is complaining that they can connect to prt y on IP x with telnet. They are seeing the following:
telnet x.x.x.x y
Trying x.x.x.x...
Connected to x.x.x.x.
Escape character is '^]'.
after some time the connection of course times out. Connection closed by foreign host. There is no telnet service running on this port so they cannot do anything, but they are complaining tht the fact that telnet "connects" is a security risk. I am having difficulty explaining why they are able to connect with telnet. I know it has to do with the socket layer API in Linux but I am having difficulty explaining this sufficiently. I also can't just say "this is the way linux works" to them. I am looking through "UNIX Network Programming" by W.
I'm using a single raw socket to read UDP packets from local test network with 1024 ports. Each UDP src and dest port is unique and I need access to IP and UDP header fields. I can stream and process data (in and out) at 100 mbps in linux-rt kernel with very low jitter < 250 usec, 10 usec nominal.
I'd like to prevent kernel from issuing ICMP port unreachable errors back to the sending host, however, I don't want to create 1024 vanilla UDP sockets and bind to each one because of resource constraints. Currently, I'm using iptables to drop the outbound port unreachable messages. Does anyone know of a way (programmatic using C code) to prevent the ICMP unreachable traffic? Perhaps an IOCTL or socket option? I also tried changing /proc/sys/net/ipv4/icmp_ratelimit but that seemed to have no effect. By default the ratemask is set for dest unreachables and a variety of ratelimit values did not change any behavior that I could see.
I have written one simple code which is posted here. i want to fetch the Mac Address on socket descriptor which is returned after accept () call.
Code:-
#include<stdio.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/in.h>
[code].....
VERY new to linux, erm but I have an issue that needs solving!I recently moved to university, where their network blocks sftp port 22, this means that I cannot connect to my FTP server which is running a version of linux.Now I've got this ftp server connected to a seedbox and it was created using the following walk through..Code:I have written this guide for a friend, but I though it would be useful for others as well.
There are several guides floating around, but I found that most always cock up in some way. This one is tried and tested to work on Debian Etch (on an OVH rps, but should apply to most servers).If there is a new stable release of rtorrent/libtorrent then I will update this guide to show you how to update it (without reinstalling the whole server).
At the bottom there are also instructions to install ftp access & some network monitoring software.Basically, I would really like someone to be able to construct the commands on how to change the listen port for sftp connection on linux or add another port to the list that Linux would use so that I could put in through putty.
I edited "sshd_config" file and changed port 22 to a new port. After I restart ssh, it listens on port 22 and the new port. How can I disable SSH to listen on port 22? I'm using Debian.
View 6 Replies View Relatediam just trying to connect to server which accepts one client and server will read(blocking operation) infinitely, but After closing the client socket the server "read operation" is returning zero and "errno variable(in errno.h)" value is also zero. how can i detect whether a client socket is closed/active..?
client.c
Serv_Addr.sin_family = AF_INET;
Serv_Addr.sin_addr.s_addr = inet_addr("127.0.0.1");
Serv_Addr.sin_port = htons(26553);
if( 0 > connect (Serv_Fds,&Serv_Addr,sizeof(Serv_Addr)) )
{
perror("connect");
return 0;
[Code]....
Consider the following program:
Code:
#include <stdio.h>
#include <stdint.h>
[code]...
I'll explain this in one sentence: Is it possible to program a port-binding shellcode in which people across the Internet can connect to, without being thwarted by the router blocking their data because the port its bound to doesn't allow port-forwarding
View 2 Replies View RelatedI have a few external IP's assigned to me by my ISP. I have IPcop as my router/firewall. I am wondering how to bind 1 of my external ip's to my internal ip address. So I do not have to port forward, etc. For Example, 77.77.77.77 to 192.168.1.123 and on the server it see's the external IP address.
View 2 Replies View RelatedWhen I do netstat -pantu it shows a dash where the pid would be. I have also checked lsof -i and see no pid associated with the port. How do I find what program is keeping the port open?
View 1 Replies View RelatedI am running Ubuntu 64-bit and I have been trying to set up an ssh connection between the Ubuntu server and a Windows 7 client (using putty) and when I enter the command:
Code:
sudo netstat --inet -lpn | grep sshd
I get the following:
[code]....
I dont know for what reason, since 2 days, I started having this message whenever I try to start httpd.I commented "Listen 443", restarted httpd started correctly. I needed to comment "listen 443" in order to be able to start httpdWhat is strange is when I do
Code:
telnet mylinux 443
it responds
[code]...
I dont know for what reason, I started having this message whenever I try to start httpd.
I commented "Listen 443", restarted httpd started correctly.
I issued "lsof -iTCP:443", I get
Quote:
I can not understand where this come from and why. It seems that it is IPV6 protocol which is in fact not enabled on the network card.
Also, I can not find or dont know where 443 is configured apart from ssl.conf or httpd.conf
Today, I have added xrdp applications in order to be able to connect using RDP.