Search Results

Search found 3538 results on 142 pages for 'tcp hijacking'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 26/142 | < Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >

  • Non-blocking TCP buffer issues.

    - by Poni
    Hi! I think I'm in a problem. I have two TCP apps connected to each other which use winsock I/O completion ports to send/receive data (non-blocking sockets). Everything works just fine until there's a data transfer burst. The sender starts sending incorrect/malformed data. I allocate the buffers I'm sending on the stack, and if I understand correctly, that's a wrong to do, because these buffers should remain as I sent them until I get the "write complete" notification from IOCP. Take this for example: void some_function() { char cBuff[1024]; // filling cBuff with some data WSASend(...); // sending cBuff, non-blocking mode // filling cBuff with other data WSASend(...); // again, sending cBuff // ..... and so forth! } If I understand correctly, each of these WSASend() calls should have its own unique buffer, and that buffer can be reused only when the send completes. Correct? Now, what strategies can I implement in order to maintain a big sack of such buffers, how should I handle them, how can I avoid performance penalty, etc'? And, if I am to use buffers that means I should copy the data to be sent from the source buffer to the temporary one, thus, I'd set SO_SNDBUF on each socket to zero, so the system will not re-copy what I already copied. Are you with me? Please let me know if I wasn't clear.

    Read the article

  • Android: Streaming audio over TCP Sockets

    - by user299988
    Hi, For my app, I need to record audio from MIC on an Android phone, and send it over TCP to the other android phone, where it needs to be played. I am using AudioRecord and AudioTrack class. This works great with a file - write audio to the file using DataOutputStream, and read from it using DataInputStream. However, if I obtain the same stream from a socket instead of a File, and try writing to it, I get an exception. I am at a loss to understand what could possibly be going wrong. Any help would be greatly appreciated. EDIT: The problem is same even if I try with larger buffer sizes (65535 bytes, 160000 bytes). This is the code: Recorder: int bufferSize = AudioRecord.getMinBufferSize(11025, , AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT); AudioRecord recordInstance = new AudioRecord(MediaRecorder.AudioSource.MIC, 11025, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, bufferSize); byte[] tempBuffer = new byte[bufferSize]; recordInstance.startRecording(); while (/*isRecording*/) { bufferRead = recordInstance.read(tempBuffer, 0, bufferSize); dataOutputStreamInstance.write(tempBuffer); } The DataOutputStream above is obtained as: BufferedOutputStream buff = new BufferedOutputStream(out1); //out1 is the socket's outputStream DataOutputStream dataOutputStreamInstance = new DataOutputStream (buff); Could you please have a look, and let me know what is it that I could be doing wrong here? Thanks,

    Read the article

  • Non-blocking TCP connection issues.

    - by Poni
    Hi! I think I'm in a problem. I have two TCP apps connected to each other which use winsock I/O completion ports to send/receive data (non-blocking sockets). Everything works just fine until there's a data transfer burst. The sender starts sending incorrect/malformed data. I allocate the buffers I'm sending on the stack, and if I understand correctly, that's a wrong to do, because these buffers should remain as I sent them until I get the "write complete" notification from IOCP. Take this for example: void some_function() { char cBuff[1024]; // filling cBuff with some data WSASend(...); // sending cBuff, non-blocking mode // filling cBuff with other data WSASend(...); // again, sending cBuff // ..... and so forth! } If I understand correctly, each of these WSASend() calls should have its own unique buffer, and that buffer can be reused only when the send completes. Correct? Now, what strategies can I implement in order to maintain a big sack of such buffers, how should I handle them etc'? And, if I am to use buffers that means I should copy the data to be sent from the source buffer to the temporary one, thus, I'd set SO_SNDBUF on each socket to zero, so the system will not re-copy what I already copied. Are you with me? Please let me know if I wasn't clear.

    Read the article

  • Using boost asio for pub/sub style tcp in a game loop

    - by unohoo
    I have been reading through the boost asio documentation for a couple of hours now, and while I think the documentation is really great, I am still left a bit confused on how to implement the system that I need. I have to stream info, from a game engine, to a list of computers over tcp. One snag is that, unlike traditional pub/sub, the computer that does the distribution of info is actually the computer that has to connect to the subscribers as well (instead of the subscribers registering with the publisher). This is done via a config file - a list of ip's/ports along with the data that they each require. The subscribers listen, but do not know the ip of the publisher. (As a side note, I'm quite new to network programming, so maybe I'm missing something .. but it's strange that I do not find much information regarding this style of "inverted" client-server model..) I am looking for suggestions for the implementation of such a system using boost asio. Of course I have to integrate the networking into an already existing engine, so with regards to that: What would be a good way to handle messages being sent to multiple computers every frame? Use async_write, call io_service.run and then reset every frame? Would having io_service.run have its own thread be better? Or should I just use threads and use blocking writes?

    Read the article

  • implementing a Intelligent File Transfer Software in java over TCP/IP

    - by whyjava
    Hello I am working on a proposal where we have to implement a software which can move files between one source to destination.The overall goal of this project is to create intelligent file transfer.This software will have three components :- 1) Broker : Broker is the module that communicates with other brokers, monitors files, moves files, retrieves configurations from the Configuration Manager, supplies process information for the monitor, archives files, writes all process data to log files and escalates issues if necessary 2) Configuration Manager :Configuration Manager is a web-based application used to configure and deploy the configuration to all brokers. 3) Monitor : Monitor is a web-based application used to monitor each Broker in the environment. This project has to be built up in java and protocol for file transfer in tcp/ip. Client does not want to use FTP. File Transfer seems very easy, until there are several processes who are waiting to pick the file up automatically. Several problems arise: How can we guarantee the file is received at the destination? If a file isn’t received the first time, we should try it again (even after a restart or power breakdown) ? How does the receiver knows the file that is received is complete? How can we transfer multiple files synchronously? How can we protect the bandwidth, so file transfer isn’t blocking other processes? How does one interoperate between multiple OS platforms? What about authentication? How can we monitor het workflow? Auditing / logging Archiving Can you please provide answer to some of these? Thanks

    Read the article

  • Remoting connection over TCP

    - by Voyager Systems
    I've got a remoting server and client built. The server is set up as such: BinaryServerFormatterSinkProvider serverProv = new BinaryServerFormatterSinkProvider(); serverProv.TypeFilterLevel = TypeFilterLevel.Full; BinaryClientFormatterSinkProvider clientProv = new BinaryClientFormatterSinkProvider(); IDictionary props = new Hashtable(); props["port"] = port; TcpChannel channel = new TcpChannel( props, clientProv, serverProv ); ChannelServices.RegisterChannel( channel, false ); RemotingConfiguration.RegisterWellKnownServiceType( typeof( Controller ), "Controller", WellKnownObjectMode.Singleton ); The client is set up as such: ChannelServices.RegisterChannel( new TcpChannel( 0 ), false ); m_Controller = (Controller)RemotingServices.Connect( typeof( Controller ), "tcp://" + ip + ":2594/Controller" ); When I try to connect to the server from the same computer with the IP specified as 'localhost,' it connects fine. However, when I try to connect from a remote computer, not on the LAN, given the server's IP address, I receive the following exception on the client after a long wait: A connection attempt failed because the connected party did not properly respond after a period of time How can I resolve this? I'm sure it's a configuration problem because the ports are forwarded properly on the server and there is no firewall active. Thanks

    Read the article

  • Iptables config breaks Java + Elastic Search communication

    - by Agustin Lopez
    I am trying to set up a firewall for a server hosting a java app and ES. Both are on the same server and communicate to each other. The problem I am having is that my firewall configuration prevents java from connecting to ES. Not sure why really.... I have tried lot of stuff like opening the port range 9200:9400 to the server ip without any luck but from what I know all communication inside the server should be allowed with this configuration. The idea is that ES should not be accessible from outside but it should be accessible from this java app and ES uses the port range 9200:9400. This is my iptables script: echo -e Deleting rules for INPUT chain iptables -F INPUT echo -e Deleting rules for OUTPUT chain iptables -F OUTPUT echo -e Deleting rules for FORWARD chain iptables -F FORWARD echo -e Setting by default the drop policy on each chain iptables -P INPUT DROP iptables -P OUTPUT ACCEPT iptables -P FORWARD DROP echo -e Open all ports from/to localhost iptables -A INPUT -i lo -j ACCEPT echo -e Open SSH port 22 with brute force security iptables -A INPUT -p tcp -m tcp --dport 22 -m state --state NEW -m recent --set --name SSH --rsource iptables -A INPUT -p tcp -m tcp --dport 22 -m recent --rcheck --seconds 30 --hitcount 4 --rttl --name SSH --rsource -j REJECT --reject-with tcp-reset iptables -A INPUT -p tcp -m tcp --dport 22 -m recent --rcheck --seconds 30 --hitcount 3 --rttl --name SSH --rsource -j LOG --log-prefix "SSH brute force " iptables -A INPUT -p tcp -m tcp --dport 22 -m recent --update --seconds 30 --hitcount 3 --rttl --name SSH --rsource -j REJECT --reject-with tcp-reset iptables -A INPUT -p tcp -m tcp --dport 22 -j ACCEPT echo -e Open NGINX port 80 iptables -A INPUT -p tcp --dport 80 -j ACCEPT echo -e Open NGINX SSL port 443 iptables -A INPUT -p tcp --dport 443 -j ACCEPT echo -e Enable DNS iptables -A INPUT -p tcp -m tcp --sport 53 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT iptables -A INPUT -p udp -m udp --sport 53 --dport 1024:65535 -m state --state ESTABLISHED -j ACCEPT And I get this in the java app when this config is in place: org.elasticsearch.cluster.block.ClusterBlockException: blocked by: [SERVICE_UNAVAILABLE/1/state not recovered / initialized];[SERVICE_UNAVAILABLE/2/no master]; at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:292) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1185) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:537) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:475) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:304) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:228) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:300) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:195) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:700) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:760) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:482) at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403) Do any of you see any problem with this configuration and ES? Thanks in advance

    Read the article

  • VPN pptp connection Unable to pass through linux iptables

    - by user221844
    I have set up a windows VPN server behind Linux - Ubuntu box that is working as firewall and proxy server. Now I want people from outside to be able to connect to the VPN server, but the connection is not being established and I get on the client an error 619. I have checked the problem on the internet and it seems a firewall issue. what should I do to make the connection established through the firewall? here is below the information about my setup Firewall-External-IF-IP: 172.16.1.100 Firewall-LAN-IF-IP: 192.168.1.1 VPN-Server-IP: 192.168.1.10 and below is my iptables file content: #Generated by iptables-save v1.4.12 on Thu May 29 12:40:18 2014 *filter :INPUT ACCEPT [162000:140437619] :FORWARD ACCEPT [23282:27196133] :OUTPUT ACCEPT [185778:143961739] :LOGGING - [0:0] -A INPUT -p gre -j ACCEPT -A INPUT -s 192.168.1.10/32 -p tcp -m tcp --sport 1723 -j ACCEPT -A INPUT -s 192.168.1.10/32 -p udp -m udp --sport 1723 -j ACCEPT -A FORWARD -s 192.168.1.0/24 -o EXT_IF -j ACCEPT -A FORWARD -s 192.168.1.0/24 -i EXT_IF -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -d 192.168.1.10/32 -i EXT_IF -o INT_IF -p tcp -m tcp --dport 1723 -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A FORWARD -s 192.168.1.10/32 -i INT_IF -o EXT_IF -p tcp -m tcp --sport 1723 -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -d 192.168.1.10/32 -i EXT_IF -o INT_IF -p gre -m state --state NEW,RELATED,ESTABLISHED -j ACCEPT -A FORWARD -s 192.168.1.10/32 -i INT_IF -o EXT_IF -p gre -m state --state RELATED,ESTABLISHED -j ACCEPT -A OUTPUT -p gre -j ACCEPT -A OUTPUT -d 192.168.1.10/32 -p tcp -m tcp --dport 1723 -j ACCEPT -A OUTPUT -d 192.168.1.10/32 -p udp -m udp --dport 1723 -j ACCEPT COMMIT # Completed on Thu May 29 12:40:18 2014 # Generated by iptables-save v1.4.12 on Thu May 29 12:40:18 2014 *nat :PREROUTING ACCEPT [17865:1053739] :INPUT ACCEPT [5490:357281] :OUTPUT ACCEPT [3723:223677] :POSTROUTING ACCEPT [3726:223870] -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A PREROUTING -d 172.16.1.100/32 -i EXT_IF -p tcp -m tcp --dport 1723 -j DNAT --to-destination 192.168.1.10 -A PREROUTING -d 172.16.1.100/32 -i EXT_IF -p gre -j DNAT --to-destination 192.168.1.10 -A PREROUTING -i -h -A POSTROUTING -s 192.168.1.0/24 -o EXT_IF -j MASQUERADE COMMIT # Completed on Thu May 29 12:40:18 2014 # Generated by iptables-save v1.4.12 on Thu May 29 12:40:18 2014 *mangle :PREROUTING ACCEPT [22695965:17811993005] :INPUT ACCEPT [13818180:11522330171] :PREROUTING ACCEPT [17865:1053739] :INPUT ACCEPT [5490:357281] :OUTPUT ACCEPT [3723:223677] :POSTROUTING ACCEPT [3726:223870] -A PREROUTING -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128 -A PREROUTING -d 172.16.1.100/32 -i EXT_IF -p tcp -m tcp --dport 1723 -j DNAT --to-destination 192.168.1.10 -A PREROUTING -d 172.16.1.100/32 -i EXT_IF -p gre -j DNAT --to-destination 192.168.1.10 -A PREROUTING -i -h -A POSTROUTING -s 192.168.1.0/24 -o EXT_IF -j MASQUERADE COMMIT # Completed on Thu May 29 12:40:18 2014 # Generated by iptables-save v1.4.12 on Thu May 29 12:40:18 2014 *mangle :PREROUTING ACCEPT [22695965:17811993005] :INPUT ACCEPT [13818180:11522330171] :FORWARD ACCEPT [8527694:6271564562] :OUTPUT ACCEPT [14748508:11899678536] :POSTROUTING ACCEPT [23271280:18170828012] COMMIT # Completed on Thu May 29 12:40:18 2014 hope that I find the solution here ....!! :(

    Read the article

  • Cisco ASA5505 8.2 Multiple Outside IP to Multiple Inside IP

    - by GriffJ
    Trying to setup ASA5505. Semi working but having issues with accessing services from the outside. ASA5505 Basic License, Version 8.2. (plus upgrade to unlimited inside hosts). Alert: I'm a Cisco Noob. 321.321.39.X is a place holder for privacy. I came up with this config and tested it tonight. ASA Version 8.2(1) ! hostname <removed> domain-name <removed> enable password <removed> encrypted passwd <removed> encrypted names ! interface Vlan1 nameif inside security-level 100 ip address 172.21.36.1 255.255.252.0 ! interface Vlan2 nameif outside security-level 0 ip address 321.321.39.10 255.255.255.248 ! interface Ethernet0/0 switchport access vlan 2 ! interface Ethernet0/1 ! interface Ethernet0/2 ! interface Ethernet0/3 ! interface Ethernet0/4 ! interface Ethernet0/5 ! interface Ethernet0/6 ! interface Ethernet0/7 ! ftp mode passive dns server-group DefaultDNS domain-name <removed> access-list outside_inbound extended permit tcp any host 321.321.39.10 eq pptp access-list outside_inbound extended permit tcp any host 321.321.39.11 eq https access-list outside_inbound extended permit tcp any host 321.321.39.11 eq 993 access-list outside_inbound extended permit tcp any host 321.321.39.11 eq smtp access-list outside_inbound extended permit tcp any host 321.321.39.11 eq 1001 access-list outside_inbound extended permit tcp any host 321.321.39.11 eq 465 access-list outside_inbound extended permit tcp any host 321.321.39.11 eq domain access-list outside_inbound extended permit udp any eq domain host 321.321.39.11 eq domain access-list outside_inbound extended permit tcp any host 321.321.39.12 eq www access-list outside_inbound extended permit tcp any host 321.321.39.12 eq https access-list outside_inbound extended permit tcp any host 321.321.39.13 eq www access-list outside_inbound extended permit tcp any host 321.321.39.13 eq https access-list outside_inbound extended permit icmp any any echo-reply access-list outside_inbound extended permit icmp any any source-quench access-list outside_inbound extended permit icmp any any unreachable access-list outside_inbound extended permit icmp any any time-exceeded access-list outside_inbound extended permit icmp any any traceroute access-list outside_inbound extended permit icmp any any echo pager lines 24 logging asdm informational mtu inside 1500 mtu outside 1500 icmp unreachable rate-limit 1 burst-size 1 no asdm history enable arp timeout 14400 global (outside) 2 321.321.39.11-321.321.39.14 netmask 255.255.255.248 global (outside) 1 interface nat (inside) 1 0.0.0.0 0.0.0.0 static (inside,outside) tcp interface pptp 172.21.37.20 pptp netmask 255.255.255.255 static (inside,outside) 321.321.39.11 172.21.37.14 netmask 255.255.255.255 static (inside,outside) 321.321.39.12 172.21.37.24 netmask 255.255.255.255 static (inside,outside) 321.321.39.13 172.21.37.17 netmask 255.255.255.255 access-group outside_inbound in interface outside route outside 0.0.0.0 0.0.0.0 321.321.39.9 1 route inside 192.168.15.0 255.255.255.0 172.21.36.52 1 timeout xlate 3:00:00 timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02 timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00 timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00 timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute timeout tcp-proxy-reassembly 0:01:00 dynamic-access-policy-record DfltAccessPolicy http server enable http 172.21.36.0 255.255.252.0 inside no snmp-server location no snmp-server contact snmp-server enable traps snmp authentication linkup linkdown coldstart crypto ipsec security-association lifetime seconds 28800 crypto ipsec security-association lifetime kilobytes 4608000 telnet 172.21.36.0 255.255.252.0 inside telnet timeout 60 ssh timeout 5 console timeout 0 threat-detection basic-threat threat-detection statistics access-list no threat-detection statistics tcp-intercept webvpn ! class-map inspection_default match default-inspection-traffic ! ! policy-map type inspect dns preset_dns_map parameters message-length maximum 512 policy-map global_policy class inspection_default inspect dns preset_dns_map inspect ftp inspect h323 h225 inspect h323 ras inspect rsh inspect rtsp inspect sqlnet inspect skinny inspect sunrpc inspect xdmcp inspect sip inspect netbios inspect tftp inspect pptp inspect ipsec-pass-thru inspect http ! service-policy global_policy global prompt hostname context The servers that had static forwards did not have any outside network access. couldn't ping google.com for instance. mail server couldn't Domain POP the Barracuda spam filter from our ISP etc. So after doing some reading I removed the statics for 172.21.37.11, 12 and 13, and replaced those three with what's below.. static (inside,outside) tcp 321.321.39.11 https 172.21.37.14 https netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.11 993 172.21.37.14 993 netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.11 smtp 172.21.37.14 smtp netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.11 1001 172.21.37.14 1001 netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.11 465 172.21.37.14 465 netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.11 domain 172.21.37.14 domain netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.12 www 172.21.37.24 www netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.12 https 172.21.37.24 https netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.13 www 172.21.37.17 www netmask 255.255.255.255 static (inside,outside) tcp 321.321.39.13 https 172.21.37.17 https netmask 255.255.255.255 Now the servers (for instance 172.21.37.14) could ping the outside world again. Mail started flowing (Domain POP was successful) etc. etc. But I forgot to check if webmail worked from the outside admittedly. But the webservers at 172.21.37.17 and 172.21.37.24 still didn't respond from the outside world. Although I was able to PPTP VPN in on 321.321.39.10 (interface) which is the outside interface IP address. and it is static mapped to 172.21.37.20. So I'm thinking there must be something wrong with NAT somewhere? no response from 321.321.39.11 to 321.321.39.14.. Could anyone look over the config and please let me know what I've done wrong? Is there something I've missed? well obviously but.. please help! Thank you.

    Read the article

  • Problem with tcp server when converting to service

    - by djerry
    Hello lads, I'm working on monitoring some object (cdr-packets). I'm setting up a tcp-server and am listening on port 50043 for the packages. The program as a console application is working just fine, my server is working like it should and i'm receiving the packets. When i try to use it as a service, i cannot seem to get a client connected to my server. Is there something i need to change to deploy this as a service? Code below is from my application: this is my service class where i start protected override void OnStart(string[] args) { server = new TcpServer(); server.StartServer(); } this is the constructor of TcpServer public TcpServer() { try { _server = new TcpListener(IPAddress.Any, 50043); } catch (Exception) { _server = null; } } this is the method i call after initialising the class public void StartServer() { if (_server != null) { // Create a ArrayList for storing SocketListeners before starting the server. _socketListenersList = new ArrayList(); // Start the Server and start the thread to listen client requests. _server.Start(); _serverThread = new Thread(new ThreadStart(ServerThreadStart)); _serverThread.Start(); // Create a low priority thread that checks and deletes client // SocktConnection objcts that are marked for deletion. _purgingThread = new Thread(new ThreadStart(PurgingThreadStart)); _purgingThread.Priority = ThreadPriority.Lowest; _purgingThread.Start(); } } this is the thread that keep checking if any client tries to connect private void ServerThreadStart() { // Client Socket variable; Socket clientSocket = null; TcpSocketListener socketListener = null; while (!_stopServer) { try { // Wait for any client requests and if there is any request from any //client accept it (Wait indefinitely). clientSocket = _server.AcceptSocket(); // Create a SocketListener object for the client. socketListener = new TcpSocketListener(clientSocket); // Add the socket listener to an array list in a thread safe fashon. lock (_socketListenersList) { _socketListenersList.Add(socketListener); } // Start a communicating with the client in a different thread. socketListener.StartSocketListener(); } catch (SocketException se) { _stopServer = true; } } } when for the first time a packet waits to be read, and i get to "clientSocket = _server.AcceptSocket();", it throws an exception (service, not very good debugable) Does anyone recognize this problem or can help me? Thanks in advance

    Read the article

  • Abnormally disconnected TCP sockets and write timeout

    - by James
    Hello I will try to explain the problem in shortest possible words. I am using c++ builder 2010. I am using TIdTCPServer and sending voice packets to a list of connected clients. Everything works ok untill any client is disconnected abnormally, For example power failure etc. I can reproduce similar disconnect by cutting the ethernet connection of a connected client. So now we have a disconnected socket but as you know it is not yet detected at server side so server will continue to try to send data to that client too. But when server try to write data to that disconnected client ...... Write() or WriteLn() HANGS there in trying to write, It is like it is wating for somekind of Write timeout. This hangs the hole packet distribution process as a result creating a lag in data transmission to all other clients. After few seconds "Socket Connection Closed" Exception is raised and data flow continues. Here is the code try { EnterCriticalSection(&SlotListenersCriticalSection); for(int i=0;i<SlotListeners->Count;i++) { try { //Here the process will HANG for several seconds on a disconnected socket ((TIdContext*) SlotListeners->Objects[i])->Connection->IOHandler->WriteLn("Some DATA"); }catch(Exception &e) { SlotListeners->Delete(i); } } }__finally { LeaveCriticalSection(&SlotListenersCriticalSection); } Ok i already have a keep alive mechanism which disconnect the socket after n seconds of inactivity. But as you can imagine, still this mechnism cant sync exactly with this braodcasting loop because this braodcasting loop is running almost all the time. So is there any Write timeouts i can specify may be through iohandler or something ? I have seen many many threads about "Detecting disconnected tcp socket" but my problem is little different, i need to avoid that hangup for few seconds during the write attempt. So is there any solution ? Or should i consider using some different mechanism for such data broadcasting for example the broadcasting loop put the data packet in some kind of FIFO buffer and client threads continuously check for available data and pick and deliver it to themselves ? This way if one thread hangs it will not stop/delay the over all distribution thread. Any ideas please ? Thanks for your time and help. Regards Jams

    Read the article

  • probelm with recv() on a tcp connection

    - by michael
    Hi, I am simulating TCP communication on windows in C I have sender and a receiver communicating. sender sends packets of specific size to receiver. receiver gets them and send an ACK for each packet it received back to the sender. If the sender didn't get a specific packet (they are numbered in a header inside the packet) it sends the packet again to the receiver. Here is the getPacket function on the receiver side: //get the next packet from the socket. set the packetSize to -1 //if it's the first packet. //return: total bytes read // return: 0 if socket has shutdown on sender side, -1 error, else number of bytes received int getPakcet(char *chunkBuff,int packetSize,SOCKET AcceptSocket){ int totalChunkLen = 0; int bytesRecv=-1; bool firstTime=false; if (packetSize==-1) { packetSize=MAX_PACKET_LENGTH; firstTime=true; } int needToGet=packetSize; do { char* recvBuff; recvBuff = (char*)calloc(needToGet,sizeof(char)); if(recvBuff == NULL){ fprintf(stderr,"Memory allocation problem\n"); return -1; } bytesRecv = recv(AcceptSocket, recvBuff, needToGet, 0); if (bytesRecv == SOCKET_ERROR){ fprintf(stderr,"recv() error %ld.\n", WSAGetLastError()); totalChunkLen=-1; return -1; } if (bytesRecv == 0){ fprintf(stderr,"recv(): socket has shutdown on sender side"); return 0; } else if(bytesRecv > 0) { memcpy(chunkBuff + totalChunkLen,recvBuff,bytesRecv); totalChunkLen+=bytesRecv; } needToGet-=bytesRecv; } while ((totalChunkLen < packetSize) && (!firstTime)); return totalChunkLen; } i use firstTime because for the first time the receiver doesn't know the normal package size that the sender is going to send to it, so i use a MAX_PACKET_LENGTH to get a package and then set the normal package size to the num of bytes i have received my problem is the last package. it's size is less than the package size so lets say last package size is 2 and the normal package size is 4. so recv() gets two bytes, continues to the while condition, then totalChunkLen < packetSize because 2<4 so it iterates the loop again and the gets stuck in recv() because it's blocking because the sender has nothing to send. on the sender side i can't close the connection because i didn't ACK back, so it's kind of a deadlock. receiver is stuck because it's waiting for more packages but sender has nothing to send. i don't want to use a timeout for recv() or to insert a special character to the package header to mark that it is the last one what can i do ? thanks

    Read the article

  • how to create multiple tcp connections between server and client

    - by lowcosthighperformance
    I am new in Unix/Linux networking programming, so I have written server-client program in below.In this code there is one socket between client and server, client requests to server, then server responses from 1 to 100 numbers to client. So my question is how can we do this process with 3 socket( tcp connection) without using thread? ( e.g. First socket runs then second runs then third runs then first again .. ) Do you have any suggestion? Thank you client.c int main() { int sock; struct sockaddr_in sa; int ret; char buf[1024]; int x; sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_port = htons(SERVER_PORT); inet_pton (AF_INET, SERVER_IP, &sa.sin_addr); ret = connect (sock, (const struct sockaddr *) &sa,sizeof (sa)); if (ret != 0) { printf ("connect failed\n"); exit (0); } x = 0; while (x != -1) { read (sock, buf , sizeof(int)); x = ntohl(*((int *)buf)); if (x != -1) printf ("int rcvd = %d\n", x); } close (sock); exit (0); } server.c int main() { int list_sock; int conn_sock; struct sockaddr_in sa, ca; socklen_t ca_len; char buf[1024]; int i; char ipaddrstr[IPSTRLEN]; list_sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_addr.s_addr = htonl(INADDR_ANY); sa.sin_port = htons(SERVER_PORT); bind (list_sock,(struct sockaddr *) &sa,sizeof(sa)); listen (list_sock, 5); while (1){ bzero (&ca, sizeof(ca)); ca_len = sizeof(ca); // important to initialize conn_sock = accept (list_sock,(struct sockaddr *) &ca,&ca_len); printf ("connection from: ip=%s port=%d \n",inet_ntop(AF_INET, &(ca.sin_addr), ipaddrstr, IPSTRLEN),ntohs(ca.sin_port)); for (i=0; i<100; ++i){ *((int *)buf) = htonl(i+20); // we using converting to network byte order write (conn_sock, buf, sizeof(int)); } * ((int *)buf) = htonl(-1); write (conn_sock, buf, sizeof(int)); close (conn_sock); printf ("server closed connection to client\n"); } }

    Read the article

  • SVN Server not responding

    - by Rob Forrest
    I've been bashing my head against a wall with this one all day and I would greatly appreciate a few more eyes on the problem at hand. We have an in-house SVN Server that contains all live and development code for our website. Our live server can connect to this and get updates from the repository. This was all working fine until we migrated the SVN Server from a physical machine to a vSphere VM. Now, for some reason that continues to fathom me, we can no longer connect to the SVN Server. The SVN Server runs CentOS 6.2, Apache and SVN 1.7.2. SELinux is well and trully disabled and the problem remains when iptables is stopped. Our production server does run an older version of CentOS and SVN but the same system worked previously so I don't think that this is the issue. Of note, if I have iptables enabled, using service iptables status, I can see a single packet coming in and being accepted but the production server simply hangs on any svn command. If I give up waiting and do a CTRL-C to break the process I get a "could not connect to server". To me it appears to be something to do with the SVN Server rejecting external connections but I have no idea how this would happen. Any thoughts on what I can try from here? Thanks, Rob Edit: Network topology Production server sits externally to our in-house SVN server. Our IPCop (?) firewall allows connections from it (and it alone) on port 80 and passes the connection to the SVN Server. The hardware is all pretty decent and I don't doubt that its doing its job correctly, especially as iptables is seeing the new connections. subversion.conf (in /etc/httpd/conf.d) LoadModule dav_svn_module modules/mod_dav_svn.so <Location /repos> DAV svn SVNPath /var/svn/repos <LimitExcept PROPFIND OPTIONS REPORT> AuthType Basic AuthName "SVN Server" AuthUserFile /var/svn/svn-auth Require valid-user </LimitExcept> </Location> ifconfig eth0 Link encap:Ethernet HWaddr 00:0C:29:5F:C8:3A inet addr:172.16.0.14 Bcast:172.16.0.255 Mask:255.255.255.0 inet6 addr: fe80::20c:29ff:fe5f:c83a/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:32317 errors:0 dropped:0 overruns:0 frame:0 TX packets:632 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2544036 (2.4 MiB) TX bytes:143207 (139.8 KiB) netstat -lntp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 1484/mysqld tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1135/rpcbind tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 1351/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1230/cupsd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 1575/master tcp 0 0 0.0.0.0:58401 0.0.0.0:* LISTEN 1153/rpc.statd tcp 0 0 0.0.0.0:5672 0.0.0.0:* LISTEN 1626/qpidd tcp 0 0 :::139 :::* LISTEN 1678/smbd tcp 0 0 :::111 :::* LISTEN 1135/rpcbind tcp 0 0 :::80 :::* LISTEN 1615/httpd tcp 0 0 :::22 :::* LISTEN 1351/sshd tcp 0 0 ::1:631 :::* LISTEN 1230/cupsd tcp 0 0 ::1:25 :::* LISTEN 1575/master tcp 0 0 :::445 :::* LISTEN 1678/smbd tcp 0 0 :::56799 :::* LISTEN 1153/rpc.statd iptables --list -v -n (when iptables is stopped) Chain INPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination iptables --list -v -n (when iptables is running, after one attempted svn connection) Chain INPUT (policy ACCEPT 68 packets, 6561 bytes) pkts bytes target prot opt in out source destination 19 1304 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22 1 60 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:80 0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:80 0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW udp dpt:80 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 17 packets, 1612 bytes) pkts bytes target prot opt in out source destination tcpdump 17:08:18.455114 IP 'production server'.43255 > 'svn server'.local.http: Flags [S], seq 3200354543, win 5840, options [mss 1380,sackOK,TS val 2011458346 ecr 0,nop,wscale 7], length 0 17:08:18.455169 IP 'svn server'.local.http > 'production server'.43255: Flags [S.], seq 629885453, ack 3200354544, win 14480, options [mss 1460,sackOK,TS val 816478 ecr 2011449346,nop,wscale 7], length 0 17:08:19.655317 IP 'svn server'.local.http > 'production server'k.43255: Flags [S.], seq 629885453, ack 3200354544, win 14480, options [mss 1460,sackOK,TS val 817679 ecr 2011449346,nop,wscale 7], length 0

    Read the article

  • Internet Protocol Suite: Transition Control Protocol (TCP) vs. User Datagram Protocol (UDP)

    How do we communicate over the Internet?  How is data transferred from one machine to another? These types of act ivies can only be done by using one of two Internet protocols currently. The collection of Internet Protocol consists of the Transition Control Protocol (TCP) and the User Datagram Protocol (UDP).  Both protocols are used to send data between two network end points, however they both have very distinct ways of transporting data from one endpoint to another. If transmission speed and reliability is the primary concern when trying to transfer data between two network endpoints then TCP is the proper choice. When a device attempts to send data to another endpoint using TCP it creates a direct connection between both devices until the transmission has completed. The direct connection between both devices ensures the reliability of the transmission due to the fact that no intermediate devices are needed to transfer the data. Due to the fact that both devices have to continuously poll the connection until transmission has completed increases the resources needed to perform the transmission. An example of this type of direct communication can be seen when a teacher tells a students to do their homework. The teacher is talking directly to the students in order to communicate that the homework needs to be done.  Students can then ask questions about the assignment to ensure that they have received the proper instructions for the assignment. UDP is a less resource intensive approach to sending data between to network endpoints. When a device uses UDP to send data across a network, the data is broken up and repackaged with the destination address. The sending device then releases the data packages to the network, but cannot ensure when or if the receiving device will actually get the data.  The sending device depends on other devices on the network to forward the data packages to the destination devices in order to complete the transmission. As you can tell this type of transmission is less resource intensive because not connection polling is needed,  but should not be used for transmitting data with speed or reliability requirements. This is due to the fact that the sending device can not ensure that the transmission is received.  An example of this type of communication can be seen when a teacher tells a student that they would like to speak with their parents. The teacher is relying on the student to complete the transmission to the parents, and the teacher has no guarantee that the student will actually inform the parents about the request. Both TCP and UPD are invaluable when attempting to send data across a network, but depending on the situation one protocol may be better than the other. Before deciding on which protocol to use an evaluation for transmission speed, reliability, latency, and overhead must be completed in order to define the best protocol for the situation.  

    Read the article

  • Apache MaxClients doubt

    - by Milan Babuškov
    I have a busy Apache server serving only dynamic PHP+MySQL pages. It is a prefork Apache, version 2.2.4 with following config: KeepAlive off StartServers 8 MinSpareServers 32 MaxSpareServers 64 ServerLimit 512 MaxClients 512 MaxRequestsPerChild 4000 MaxClients/ServerLimit used to be set to 256, but I got the following error in error_log so I increased it: [error] server reached MaxClients setting, consider raising the MaxClients setting It seems to work now, but I have a doubt. Looking at MySQL log of queries, I have a couple hundred clients per seconds, but "ps ax" only shows 8, 9 or 10 processes running: [root@engine ~]# ps ax | grep http | wc -l 10 I even got this many processes when the above error message was shown in error_log. This made me investigate further. When I run netstat -a, I get something like this: tcp 0 0 engine:http adsl-105-143.teol.net:21453 TIME_WAIT tcp 0 0 engine:http 118-36.static.kds:mck-ivpip TIME_WAIT tcp 0 0 engine:http 118-36.static:oce-snmp-trap TIME_WAIT tcp 0 0 engine:http 118-36.static.kd:unifyadmin TIME_WAIT tcp 0 0 engine:http cable-188-2-25-29.dyna:4906 TIME_WAIT tcp 0 0 engine:http adsl-105-143.teol.net:21458 TIME_WAIT tcp 0 0 engine:http 109-92-83-91.dynamic.:62821 TIME_WAIT tcp 0 0 engine:http cable-89-216-142-192.:63576 TIME_WAIT tcp 0 0 engine:http 109-92-83-91.dynamic.:62819 TIME_WAIT tcp 1081 0 engine:http pttnetadsl38-36.ptt.r:50496 ESTABLISHED tcp 0 0 engine:http cable-188-2-36-196.dyn:4136 TIME_WAIT tcp 0 0 engine:http cable-89-216-142-192.:63580 TIME_WAIT tcp 0 0 engine:http cable-89-216-142-192.:63581 TIME_WAIT etc. When counting those, I get: [root@engine ~]# netstat -a | grep http | wc -l 431 Can anyone tell me what is really going on here and how to make sure my server keeps working, because I only use 50% of available RAM in machine?

    Read the article

  • IPTables Rule for Google Apps SMTP

    - by XpresServers
    I am trying to add iptables rule to allow traffic on ports 465 & 587 to google apps smtp servers. But I got not luck. My WHMCS installation works fine with google apps when I turn off iptables but iptables turn on itself again and email stop working. Please add rules to allow traffic from port 465 and 587. Following are my IPTables rules grabbed from /etc/sysconfig/iptables # Generated by iptables-save v1.3.5 on Fri Oct 5 01:33:52 2012 *filter :INPUT ACCEPT [2191:434537] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [2390:987151] :acctboth - [0:0] -A INPUT -j acctboth -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --gid-owner mailman -j ACCEPT -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --gid-owner mail -j ACCEPT -A OUTPUT -d 127.0.0.1 -p tcp -m multiport --dports 25,465,587 -m owner --uid-owner cpanel -j ACCEPT -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --uid-owner root -j ACCEPT -A OUTPUT -j acctboth -A OUTPUT -o eth0 -p tcp -m tcp --sport 587 -m state --state ESTABLISHED -j ACCEPT -A OUTPUT -o eth0 -p tcp -m tcp --sport 465 -m state --state ESTABLISHED -j ACCEPT <<IN THIS SPACE RULES ARE RELATED TO SPECIFIC IPS ONLY>> -A acctboth -i ! lo COMMIT # Completed on Fri Oct 5 01:33:52 2012 # Generated by iptables-save v1.3.5 on Fri Oct 5 01:33:52 2012 *nat :PREROUTING ACCEPT [196:12398] :POSTROUTING ACCEPT [191:15070] :OUTPUT ACCEPT [190:15010] -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --gid-owner mailman -j RETURN -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --gid-owner mail -j RETURN -A OUTPUT -d 127.0.0.1 -p tcp -m multiport --dports 25,465,587 -m owner --uid-owner cpanel -j RETURN -A OUTPUT -p tcp -m multiport --dports 25,465,587 -m owner --uid-owner root -j RETURN -A OUTPUT -p tcp -m multiport --dports 25,465,587 -j REDIRECT COMMIT # Completed on Fri Oct 5 01:33:52 2012 Thanks Hassan

    Read the article

  • mount.nfs: access denied by server while mounting (Kerberos authentication)

    - by Nick
    There's plenty of references to this error on Goggle, and even a question here with the same title, but it seems that "access denied by server while mounting" is a catch-all error. I've tried suggestions that others have used to fix this problem, but they did not work in my case. I'm trying to set-up a Kerberos-based NFS file server with shared homes for a Linux network. I'm using Ubuntu 11.04 Servers and clients. When trying to mount a share using: mount 192.168.1.115:/export/home/ /media/tmp I get: mount.nfs: access denied by server while mounting 192.168.1.115:/export/home/ This is the same if I mount it from a client machine or from the server itself. On the server, in /var/log/syslog I get: Aug 25 06:22:37 nfs mountd[1580]: authenticated mount request from 192.168.1.115:835 for /export/home (/export/home) Aug 25 06:22:37 nfs mountd[1580]: authenticated unmount request from 192.168.1.115:766 for /export/home (/export/home) Which is odd, since it says it's authenticated the request, not denying it. /etc/exports: /export *(rw,fsid=0,crossmnt,insecure,async,no_subtree_check,sec=krb5p:krb5i:krb5) /export/home *(rw,insecure,async,no_subtree_check,sec=krb5p:krb5i:krb5) On client: me@dt1:/$ rpcinfo -p 192.168.1.115 program vers proto port 100000 2 tcp 111 portmapper 100024 1 udp 37320 status 100024 1 tcp 48460 status 100003 2 tcp 2049 nfs 100003 3 tcp 2049 nfs 100003 4 tcp 2049 nfs 100227 2 tcp 2049 100227 3 tcp 2049 100003 2 udp 2049 nfs 100003 3 udp 2049 nfs 100003 4 udp 2049 nfs 100227 2 udp 2049 100227 3 udp 2049 100021 1 udp 58625 nlockmgr 100021 3 udp 58625 nlockmgr 100021 4 udp 58625 nlockmgr 100021 1 tcp 49616 nlockmgr 100021 3 tcp 49616 nlockmgr 100021 4 tcp 49616 nlockmgr 100005 1 udp 45627 mountd 100005 1 tcp 60265 mountd 100005 2 udp 45627 mountd 100005 2 tcp 60265 mountd 100005 3 udp 45627 mountd 100005 3 tcp 60265 mountd Any suggestions I could try?

    Read the article

  • Sync Vs. Async Sockets Performance in C#

    - by Michael Covelli
    Everything that I read about sockets in .NET says that the asynchronous pattern gives better performance (especially with the new SocketAsyncEventArgs which saves on the allocation). I think this makes sense if we're talking about a server with many client connections where its not possible to allocate one thread per connection. Then I can see the advantage of using the ThreadPool threads and getting async callbacks on them. But in my app, I'm the client and I just need to listen to one server sending market tick data over one tcp connection. Right now, I create a single thread, set the priority to Highest, and call Socket.Receive() with it. My thread blocks on this call and wakes up once new data arrives. If I were to switch this to an async pattern so that I get a callback when there's new data, I see two issues The threadpool threads will have default priority so it seems they will be strictly worse than my own thread which has Highest priority. I'll still have to send everything through a single thread at some point. Say that I get N callbacks at almost the same time on N different threadpool threads notifying me that there's new data. The N byte arrays that they deliver can't be processed on the threadpool threads because there's no guarantee that they represent N unique market data messages because TCP is stream based. I'll have to lock and put the bytes into an array anyway and signal some other thread that can process what's in the array. So I'm not sure what having N threadpool threads is buying me. Am I thinking about this wrong? Is there a reason to use the Async patter in my specific case of one client connected to one server?

    Read the article

  • Sync Vs. Async Sockets Performance in .NET

    - by Michael Covelli
    Everything that I read about sockets in .NET says that the asynchronous pattern gives better performance (especially with the new SocketAsyncEventArgs which saves on the allocation). I think this makes sense if we're talking about a server with many client connections where its not possible to allocate one thread per connection. Then I can see the advantage of using the ThreadPool threads and getting async callbacks on them. But in my app, I'm the client and I just need to listen to one server sending market tick data over one tcp connection. Right now, I create a single thread, set the priority to Highest, and call Socket.Receive() with it. My thread blocks on this call and wakes up once new data arrives. If I were to switch this to an async pattern so that I get a callback when there's new data, I see two issues The threadpool threads will have default priority so it seems they will be strictly worse than my own thread which has Highest priority. I'll still have to send everything through a single thread at some point. Say that I get N callbacks at almost the same time on N different threadpool threads notifying me that there's new data. The N byte arrays that they deliver can't be processed on the threadpool threads because there's no guarantee that they represent N unique market data messages because TCP is stream based. I'll have to lock and put the bytes into an array anyway and signal some other thread that can process what's in the array. So I'm not sure what having N threadpool threads is buying me. Am I thinking about this wrong? Is there a reason to use the Async patter in my specific case of one client connected to one server?

    Read the article

  • Is it possible to make a persistent connection between a Python web service and a .Net WCF Client?

    - by Ad Hock
    I have a .Net 3.5 SOAP client written in C# using the WCF. It's expecting basicHTTPBinding and a persistent connection with HTTP/1.1. I'm trying to create a Python 2.6 application that will act as a web-service for the client. My problem is that the client keeps closing the connection and opening a new one for every command to the web service. How does the .Net WCF client know to stay open when connecting with a .Net Service? When I create a dummy .Net web service the client connects fine and the connection remains persistent. From what I can tell, when connected to a .Net server, there are no special HTTP headers being sent, that makes sense since HTTP/1.1 assumes a persistent connection unless otherwise specified (right?). However, with the python web service I accept/open a connection and eventually the client will send a TCP FIN and the connection will close (the client never sends a FIN or RST when connecting to a .Net service). The communication goes something like this: Incoming -- HTTP Header for SOAP Command #1 Outgoing -- HTTP Header with a Continue Incoming -- Body of Command #1 Outgoing -- ACK Command #1 (HTTP headers and body) Incoming -- HTTP Header for SOAP Command #2 Outgoing -- HTTP Header with a Continue Incoming -- TCP FIN <Connection closes> <New connection opens and SOAP command #2 (with full HTTP headers) is sent> I'm using a SocketServer.ThreadingTCPServer as the server and a BaseHTTPServer.BaseHTTPRequestHandler for any requests. The handler is actually a derived class of that with a do_POST method to handle the HTTP headers. I've looked at WireShark captures and I'm stumped. I've tried setting socket options to SO_KEEPALIVE and SO_REUSEADDR in the server but that didn't seem to change anything. What am I missing?

    Read the article

  • How does the socket API accept() function work?

    - by Eli Bendersky
    The socket API is the de-facto standard for TCP/IP and UDP/IP communications (that is, networking code as we know it). However, one of its core functions, accept() is a bit magical. To borrow a semi-formal definition: accept() is used on the server side. It accepts a received incoming attempt to create a new TCP connection from the remote client, and creates a new socket associated with the socket address pair of this connection. In other words, accept returns a new socket through which the server can communicate with the newly connected client. The old socket (on which accept was called) stays open, on the same port, listening for new connections. How does accept work? How is it implemented? There's a lot of confusion on this topic. Many people claim accept opens a new port and you communicate with the client through it. But this obviously isn't true, as no new port is opened. You actually can communicate through the same port with different clients, but how? When several threads call recv on the same port, how does the data know where to go? I guess it's something along the lines of the client's address being associated with a socket descriptor, and whenever data comes through recv it's routed to the correct socket, but I'm not sure. It'd be great to get a thorough explanation of the inner-workings of this mechanism.

    Read the article

  • ICMP Redirect Theory VS. Application

    - by joeqwerty
    I'm trying to watch ICMP redirects in a lab using Cisco Packet Tracer (version 5.3.2) and I'm not seeing them, which leads me to believe that either my lab configuration isn't correct or my understanding of ICMP redirects isn't correct or that Packet Tracer doesn't support/use ICMP redirects. Here's what I believe to be true regarding ICMP redirects: Routers send ICMP redirects when all of these conditions are met: The interface on which the packet comes into the router is the same interface on which the packet gets routed out. The subnet or network of the source IP address is on the same subnet or network of the next-hop IP address of the routed packet. The datagram is not source-routed. The router kernel is configured to send redirects. I have the lab set up in Cisco Packet Tracer as displayed in the image and would expect to see an ICMP redirect from Router1 when pinging from PC1 to PC3. I'm not seeing the ICMP redirect and it looks like Router1 is actually routing all of the packets via Router2. I have IP ICMP debugging enabled on Router1 (and Router2) and I'm not seeing any ICMP redirect activity in either console. I'm also not seeing a route to the PC3 network in the routing table on PC1, which I think confirms that the ICMP redirect is not occurring. I'm using only static routing on Routers 1 and 2. Is my understanding of ICMP redirects incorrect, or is there a problem with my lab configuration or does Packet Tracer not support/use ICMP redirects?

    Read the article

  • Socket(TCPIP) Unstable

    - by Lee Kwan Wee
    I have a setup of a SCPI server in a Win7 PC and have 2 other programs talking to it locally(127.0.0.1) over TCPIP socket 5025 and 5029. This worked well and stable in a fresh PC, but when we moved it into our production lines and the IT dept added their policies and stuff, it became unstable. The PC is connected to the production floor server but both of the programs are running locally in the PC. The connection tends to be disconnected when there is an idle period. And it takes 5-6times to refreshing the connection to get it back. I'm not a programmer myself, so I'm hoping to see if anyone here can help with some answers. Thank you very much!! Regards, KwanWee.

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 22 23 24 25 26 27 28 29 30 31 32 33  | Next Page >