Ubuntu Networking :: Intermittent Internet Connection - Freezes And Doesn't Receive Few Packets
Mar 31, 2010
I'm having problems with my internet connection; it seems to be working fine then every other click of a page there is no connection, then I click it again a second later and it works. I am using a wired network connection plugged into an addon wireless router.
When I use ping under network tools it seems to be fine, then freezes halfway through and doesn't receive those few packets, giving me a transmission percentage of about 70%.
I have a Dell laptop with a bcm4312 wireless card. Every once in a while though, the laptop is unable to send or receive any data for 30 seconds. The connection is not dropped, and nothing shows up in any system logs. Both the wl and b43 drivers have this problem, but it works fine under vista.
I have set up one of my linux box as link load balancer for two ADSL connection. After deployment, I have found out that instead of being fast, it has become slow. What I have observed that my request get out to internet but comes back intermittently. Is this a standard scenario ?
i have a linux server runnig oracle applications. i need to access this server from putty using ssh through internet. i did by registering my static ip with the dnydns.org and i am able to connect to the server. but now there is no security to authenticate any user as any one knowing the password can login to it.
i thought of configuring the firewall of linux server but the client ip`s are not static and they change continiously. so thought of keeping one more pc between the server and the router which will do the work of authenticating. but i am confuse as how to configure it to allow the packets coming from the internet after authenticating and to by pass the packets generated from internal LAN?
I've got an application that compiles in Windows and Linux and is using UDP multicast to communicate. I'm running it on a Windows machine, a Linux machine and a small board (Gumstix) that is running Linux as well. The Windows and Linux machines have no problems sending/receiving packets with each other. The Gumstix and Linux machines have no problems sending/receiving packets with each other. The Gumstix can also send/receive packets with two instances of the application both running on the Gumstix.
But when running on the Gumstix I can send udp multicast packets to Windows, but cannot receive them. (It works if I do point to point with a known IP port#, but not multicast.) I can run tcpdump on the Gumstix and see the packets, but they are not being received on my socket. Here's what tcpdump (running on the Gumstix) outputs when sending the same packet from different sources. Notice the IP header ID and flags (don't fragment) are different when coming from Windows.
WINDOWS to Gumstix -7:-45:-2.015784 IP (tos 0x0, ttl 15, id 35331, offset 0, flags [none], proto: UDP (17), length: 444) 172.30.42.3.1165 > 239.255.183.180.47028: UDP, length 416
LINUX to GUMSTIX -7:-43:-38.451991 IP (tos 0x0, ttl 15, id 0, offset 0, flags [DF], proto: UDP (17), length: 444) 172.30.42.13.32771 > 239.255.183.180.47028: UDP, length 416
GUMSTIX to GUMSTIX -7:-33:-10.955608 IP (tos 0x0, ttl 15, id 0, offset 0, flags [DF], proto: UDP (17), length: 444) 172.30.42.110.1025 > 239.255.183.180.47028: UDP, length 416
I've tried everything I can think of to get this to work but am not getting anywhere. Also I'm pretty inexperienced when it comes to Linux. Anything I could try to be able to receive udp multicast packets from Windows?
Assume this: Machine A sends a packet to machine B, no application in machine B is waiting for the packet, Now: What happens in kernel? What happens to this packet exactly?
I am working on uClinux/almost same as Linux. I am new to socket programming. I have two micro controllers running on same code. Simple run with arguments mean send merged string. run 1st micro controller (Send): ./Name "anystring" run 2st micro controller (Recive):/Name
My code is: int receive() { // Create socket int sock_fd; struct sockaddr_in addr; char buffer[kBufferSize]; int bytes_received=0; int addr_len = sizeof(addr); printf("receive start "); sock_fd = socket(AF_INET, SOCK_DGRAM, 0); if ( sock_fd == -1 ) { printf("receive Create "); // Error occurred return 0; } printf("Res Create sucee "); // Create address from which we want to receive, and bind it memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = INADDR_ANY; addr.sin_port = htons(kPortNumber); if ( bind(sock_fd, (struct sockaddr*)&addr, sizeof(addr)) < 0 ) { printf("receive bind "); // Error occurred return 0; } printf("Bind Succeful sucee "); while ( 1 ) { // Receive a message, waiting if there's nothing there yet bytes_received = recvfrom(sock_fd, buffer, kBufferSize-0, 0, (struct sockaddr*)&addr, &addr_len); if ( bytes_received < 0 ) { // Error occurred printf("receive bytes "); return 0; } printf(" bytes_received succeful "); printf("Ressocketstring : %s ",buffer); memset(Ressocketstring,0x00 , sizeof(Ressocketstring)); strcpy(buffer,Ressocketstring); printf("Ressocketstring : %s ",Ressocketstring); printf(" "); printf("Hello Receive finished"); // Now we have bytes_received bytes of data in buffer. Print it! fwrite(buffer, sizeof(char), bytes_received, stdout); } } int transmit(char * data, int length) { int sock_fds[kMaxSockets]; // Obtain list of all network interfaces /* struct ifaddrs *addrs; if ( getifaddrs(&addrs) < 0 ) { // Error occurred return 0; } */ // Loop through interfaces, selecting those AF_INET devices that support broadcast, but aren't loopback or point-to-point struct sockaddr_in addr; int number_sockets = 0; struct hostent *he; /* const struct ifaddrs *cursor = addrs; while ( cursor != NULL && number_sockets < kMaxSockets ) { if ( cursor->ifa_addr->sa_family == AF_INET && !(cursor->ifa_flags & IFF_LOOPBACK) && !(cursor->ifa_flags & IFF_POINTOPOINT) && (cursor->ifa_flags & IFF_BROADCAST) ) { // Create socket*/ sock_fds[number_sockets] = socket(AF_INET, SOCK_DGRAM, 0); if ( sock_fds[number_sockets] == -1 ) // Error occurred { printf("Error Create "); return 0; } he = gethostbyname((char *)BCASTADDRESS) ; if (he==NULL ) {printf("Error gethostbyname "); herror("gethostbyname"); printf("Error host "); exit(1); } printf("Res He "); // Create address from which we want to send, and bind it memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr = *((struct in_addr *)he->h_addr);//((struct sockaddr_in *)cursor->ifa_addr)->sin_addr; addr.sin_port = htons(kPortNumber); if ( bind(sock_fds[number_sockets], (struct sockaddr*)&addr, sizeof(addr)) < 0 ) { // Error occurred printf("Error bind "); return 0; } // Enable broadcast int flag = 1; if ( setsockopt(sock_fds[number_sockets], SOL_SOCKET, SO_BROADCAST, &flag, sizeof(flag)) != 0 ) // Err occur { printf("Error Enable "); return 0; } number_sockets =1; printf("Succes 1 "); printf("transmit Create "); // Initialise broadcast address memset(&addr, 0, sizeof(addr)); addr.sin_family = AF_INET; addr.sin_addr.s_addr = INADDR_BROADCAST; addr.sin_port = htons(kPortNumber); // Send through each interface int i; for ( i=0; i<number_sockets; i++ ) { if ( sendto(sock_fds[i], data, length, 0, (struct sockaddr*)&addr, sizeof(addr)) < 0 ) { printf("Error Send "); // Error occurred return 0; } printf("Succes 2 "); } return 1; } void MergeMessage( ) { memset(socketstring,0x00,sizeof(socketstring)); sprintf(socketstring,"%s@%s@%s@%s@%s@%s@%s@%s@%s@%s@%s ",Tmeg.s1,Tmeg.s2,Tmeg.s3,Tmeg.s4,Tmeg.s5,Tm eg.s6,Tmeg.s7,Tmeg.s8,Tmeg.s9,Tmeg.s10,Tmeg.s11); printf(" MergeSocketMessage : %s ",socketstring); } int main (int argc, char** argv) { int fd=0,bdc=0; struct ifreq ifr; printf("Tsarting man "); fd = socket(AF_INET, SOCK_DGRAM, 0); strncpy(ifr.ifr_name, "eth0", IFNAMSIZ-1); ioctl(fd, SIOCGIFADDR, &ifr); close(fd); memset(MYIP,'-',sizeof(MYIP)); memset(BCASTADDRESS,'-',sizeof(BCASTADDRESS)); strcpy(MYIP, inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr)); printf("Etho: %s ,len:%d ", MYIP,strlen(MYIP)); for(bdc=strlen(MYIP);MYIP[bdc-1]!='.';bdc--) {} strncpy(BCASTADDRESS,MYIP,bdc-1); strcat(BCASTADDRESS,".255"); printf("BCASTADDRESS: %s ,len:%d ", BCASTADDRESS,strlen(BCASTADDRESS)); printf("Initial Broad Cast message "); { /*s0"0" (id=76) s1"500" (id=77)s2"100" (id=78)s3"100" (id=78)s4"startVD" (id=79) s5"lighting" (id=80)s6"reading" (id=81)s7"Anna" (id=82)s8"0" (id=76) s9"";s10"" (id=64)s11"" (id=64)*/ strcpy(Tmeg.s0,"0"); strcpy(Tmeg.s1,"500");strcpy(Tmeg.s2,"100");strcpy(Tmeg.s3,"100"); strcpy(Tmeg.s4,"startvd");strcpy(Tmeg.s5,"lighting");strcpy(Tmeg.s6,"reading"); strcpy(Tmeg.s7,"anna");strcpy(Tmeg.s8,"0"); } MergeMessage (Tmeg); if( strlen(argv[1]) ) { //strcpy(socketstring,Tmeg,sizeof(Tmeg)); if(transmit(socketstring, strlen(socketstring) ) ) { printf(""%s" transmitted. ", socketstring); } else { printf("Error occurred: %s ", strerror(errno)); return 1; } } else { for( ; ; ) { if ( argc < 2 ) // No argument: Just listen { printf("Listening... "); if ( !receive() ) { printf("Error occurred: %s ", strerror(errno)); return 1; } return 0; } } } printf("Finished "); return 0; } //////////////// .h file is ///////////// //#define WIN32_LEAN_AND_MEAN// Exclude rarely-used stuff from Windows headers #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <net/if.h> #include <fcntl.h> #include <netdb.h> #include <signal.h> #include <sys/wait.h> #include <sys/ioctl.h> #define SubLen50 //#include <ifaddrs.h> #include <errno.h> char MYIP[20]; char BCASTADDRESS[20]; typedef struct { char s0[SubLen]; char s1[SubLen]; char s2[SubLen]; char s3[SubLen]; char s4[SubLen]; char s5[SubLen]; char s6[SubLen]; char s7[SubLen]; char s8[SubLen]; char s9[SubLen]; char s10[SubLen]; char s11[SubLen]; }msg_struct; msg_struct Sendmsg; msg_struct Tmeg; //Recivemsg; Boolean pri[6]; char socketstring[SubLen*12]; char Ressocketstring[SubLen*12]; int kBufferSize = (SubLen*12);
I need to receive a number of raw ethernet packets (say, 100 packets) into a user-mode accessible buffer large enough to hold all the packets. The way I have done this so far is by looping over the recvfrom() system call 100 times, passing an incremented pointer addressing the location in my buffer to store the packet. Is there a way to receive the 100 packets into my buffer with one system call, perhaps by instructing the kernel to DMA the 100 packets into my buffer?
I am trying to do something outlandish with iptables (or so I think!).I have a source sending udp packets to a destination (say dst11). Using port mirroring I am able to get all these packets to a different machine (say dst22). I am able to see these packets on dst22 interface using tcpdump.I want to analyze the packets on dst22. So what I do is put dst22 interface in promiscuous mode (using ifconfig eth0 promisc). This in theory should get the packet through the MAC layer. Now using iptables I am trying to DNAT the packets in nat prerouting to change the packets destination IP to dst22's interface and change the destination port.
I attempted to download and install Linux XP and the installation appeared to be a success. But after install of course the system reboots. Well after rebooting before opening up the desktop it forces me to set up the domain or something It would not recognize my internet/network connection. My ISP provider doesn't use any type of authentic. My internet connection is automatically configured through my modem. How do I get Linux XP to recognize my internet connection and finish the final process so that I can load into desktop ?? I also had a very similar problem with Linux Ubuntu Studio as well. I installed it and I was able to get into the desktop but still was unable to establish an internet connection.
I have installed Centos 5 on my laptop.And I have installed Oracle databases and also VMWARE server 2 software on it.But I see no page opens in firefox browser on this laptop.I can't understand why.The laptop doesn't have internet connection. But the VMWare web access page where we can login to console and create virtual machines doesn't require internet access.I am a newbie to linux and also network issues.How to figure out what is the problem? Are there any step by step guide to investigate this issue?All the pages I open get stuck with "waiting for abc.com" etc.It never opens.Javascript is enabled for this browser.
I can connect to the internet on Win7 without issue. Boot to Ubuntu 10.10 amd64 & it works sometimes & sometimes it doesn't.
I've attached 4 screen photos; 2 when internet is working (Working ifcomfig & Working route -n) & 2 when internet is NOT-working (NonWorking ifcomfig & NonWorking route -n).
The 1st I notice when looking @ working ifconfig is line 3 under eth0, inet addr:192.168.1.5 Bcast:192.168.1.255 Mask:255.255.255.0, is missing on NonWorking ifconfig.
Using my usb mobile broadband dongle I am able to access the internet about 25% of the time. I am able to make a connection to the '3' wireless network 100% of the time, but often Mozilla and all other applications that rely on an internet connection do not recognise that this connection has been successfully established, and give me error messages claiming there is no internet connection.
I can't discern any pattern as to whether the connection will be recognised or not. When it isn't recognised, the only solution is to disconnect and reconnect to the network. Sometimes this works and sometimes it doesn't. Sometimes restarting the computer fixes the problem, and sometimes it doesn't. I also have access to a wireless network at uni. I have no problems using this network whatsoever. Housemates using the same dongle on Windows have no problems. I'm using an Acer Aspire one, the dongle is a Huawei e220, I'm running Ubuntu 9.10. I have only recently reinstalled the operating system and have not needed to mess around with any network settings to get the usb dongle to 'work' the way it is currently.
I've got UNE 10.10 installed on a Samsung N150 that uses the RTL8192E for wireless. When the wireless works then it generally works okay, but I'm having problems with reboots and long-running connections. This is different to the mass of posts (mainly from 2009) about the card not working at all, so I started a new thread.Basically, 90%+ of cold boots result in a successful wireless connection, with Network Manager remembering my WPA password.
When the wireless is up then it never obviously drops out, but I've got an app with a long-running connection that seems to disconnect itself occasionally. Looking at Wireshark then it appears that there are a number of retransmits, and a big batch just before it disconnects (which implies that the app is dropping its connection because it thinks the other end disappeared). Running the app on another machine with a different card but through the same release of Ubuntu and the app and the same router doesn't result in retries or drop-outs.On the times when a cold boot doesn't successfully reconnect then it asks for the WPA password, then continues trying, then asks for the WPA password again, then continues trying, then asks...and so on until I rmmod and modprobe the driver.
I originally had problems with the machine refusing to restore after a hibernate/suspend, but this was solved by a tip to rmmod the driver on hibernate/suspend and modprobe it on restore.The wireless will now work okay on some restores, but is more likely to repeat the behaviour described above for the failed cold boot.
Attached is a file with some snippets from dmesg around the time of the wireless failure, and the log of what it does after a remove and re-add for comparison of the "correct" messages.
I have been running 10.10 server with no GUI for a few months without issue. I decided to install ubuntu desktop (GUI), because I want to turn it into a media server, and I'm finding that my Internet browsing fails intermittently. i.e. I can get [URL] sometimes and sometimes not. I have tried traceroute and found that I do not reach my local router on addresses that fail, and yet I get a full trace on addresses that are ok. Ping tests too.I remember from some time ago that the GUI may cause a network problem but I'm not sure. By the way, other computers on the network can access this host through Samba so the NIC is working fine.
After having trouble with Ubuntu 9.10 (solved with a nice modemmanager bug fix by a great user) here we are with the new Lucid Lynx: until now, just to be safe, I am trying my Nokia CS-10 USB stick (for wireless 3g connection) with the Live Ubuntu, and it doesn't even get recognized (no red light or anything else)...
In the last week I have noticed that sometimes my Mobile Broadband connection just goes off without me doing anything! I have credit on the dongle account, so it isn't that. I'm using fedora 14 on an acer aspire one netbook. Dongle is a Huawei E160 on o2 here in the UK Kernel is 2.6.35.11-83.i686.fc14
Sometimes unplugging and replugging the usb dongle works. Othertimes, I have to leave it out for several hours. It does seem to happen daily, though.
i have just installed 10.10 under wubi, first time trying to use this network card under ubuntu. works fine on XP where it connects with good signal strength to a zyxel p-600 b/g router (my 3 other machines also connect fine to this router)
i am using WPA2, it takes 30secs to 1min to connect in the first place, then runs slowly and with intermittent disconnects, reports good signal strength in network manager.
i have been fortunate enough to have 3 machines that run ubuntu flawlessly out of the box..
I am a convert from Ubuntu (9.04 kept freezing on my laptop; when it did work, many packages it seemed were outdated--ie only Eclipse 3.2, rdesktop was messed up [and apparently is also in Fedora]), and I am having some trouble with getting my wireless working.I am running Fedora 11.First off, there is a problem when trying to connect when using DHCP. NetworkManager gets to the second green dot, and then after a short while I am given a message that the connection was disconnected.
Configuring the interface manually, not using DHCP, allows the connection to complete. However, the internet is very slow. There is a 15-30 sec delay before website loading actually commences, and then another delay each time an ad must be fetched from another server.How can I fix this delay? I know I have encountered it in earlier versions of Ubuntu, but I can't remember how I fixed it.About the rdesktop problem, if anyone is able to help [maybe I should post another thread?], the cursor color (the color of the pointer) is inverted---where it should be white it is black, and where it should be black it is white. I use rdesktop a lot to connect to my terminal server in my basement. Any idea how to fix it?
I just upgraded to Ubuntu 10.10 because I was facing internet problems with previous Ubuntu 9.04 after I upgraded it with downloaded software. And now, 10.10 connects to wireless, but shows web-page some-times and repeatedly disconnects. Earlier it wasn't reaching Internet at all. Some of the topics here helped a lot. But this intermittent internet seems not going anywhere. Wired Internet connects easily though.
I've tried :-
-disabling ipv6..... first in Firefox, then in Kernel also -Setting DNS.....System> Preferences> Network Connections -setting static Ip
I am trying to build a socket to retrieve the ethernet packets from ECU(I do not know much about the ECU). When i run my code on windows there is no problem and the code runs correctly. But when i run my code on Debian it gets stuck at s.recv(1024).
I have already set static ip in /etc/network/interfaces as follows:
Code: Select all import socket import sys HOST = "160.48.199.91" port = 30490 s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_UDP) s.bind((HOST, 30490)) while True: data = s.recvfrom(1024) print(data)
There is no LAN or Router. When i check netstat -s i see that there are 0 UDP and 0 TCP messages received. But when i check in Wireshark on Debian i could see the displayed UDP packets. Does it mean that the UDP packets are reaching the Raspberry Pi but not received by Debian ? Or are these packets being dropped?
I'm having a bizarre problem where my network connection stops working randomly. At first I thought it was a DNS issue since Firefox simply chilled out on "Looking up [hostname]" until it timed out, but after further investigation (pinging IP's, "host" and "dig" being unable to reach servers) it became apparent that I couldn't even access the DNS servers i.e. the Wicked Connection of the East was most sincerely dead.
There are two strange things about this: one, there are no errors except "timeout". The network manager is happy, Firefox is happy until the lookup fails... Two, the failures only start *after* DHCP configuration. DHCP configuration never has any trouble sending or receiving packets. I'm going to try static IP and whatnot to see if that helps, more information later.
I have a router which makes two ppp connections. PPP0 is my default route and is an uncapped ADSL. PPP1 is a Local Only (South Africa) account which has DNS resolving to its IP. PPP1 allows certain connections in. I want all packets coming in on PPP1 to be marked so that after they have been routed through our local servers they can go back out over PPP1. Both connections use dynamically assigned ip addresses. I want to use PPP0 to make a connection to one of our stores, but when our stores connect to us they will be using PPP1. All packets from these incoming connections will need to be routed back over PPP1.
I have a router/modem linux box, connection to DSL through PPP.I also use an OpenVPN service, to which this box connects.My problem is that the speed cap of the VPN is just half that of the DSL connection. I don't need it for internet browsing. Is there a way I can route all the http traffic coming from the client computers (or all of the traffic will do too) through the normal connection?As of now I can only route all traffic either on VPN or normal PPP
we are using Red hat enterprise 5.4 for our internet connection with following ip's
eth0: 192.168.1.2 (local lan) eth1: 114.143.28.240 (static ip address for 1st isp) eth2: 192.168.100.149 (2nd isp modem connected with lan cable)
first isp i.e tata internet connected to the internet and working very well
now i want 2nd isp to work when the first isp goes down, i had configured all dns in the resolve.conf and squid.conf, when i switch off the 1st isp for checking that failover is working or not i cannot get internet packets from the second isp.
I'm running Lucid (10.04), dualboot vista, but I'm having some issues with my wireless USB dongle. Previously (in a different) location, the network wasn't showing in my wireless network tab, and that was never resolved. But now I'm in a new place, and what I'm finding is that my network is showing up in the networks tab, and I can select it, enter the PSK, and it starts to interrogate, but never seems to manage all the way through to getting internet.
Im not sure whether the machine is able to connect to the network, but not the wider internet, or what. The only indication I'm getting is that its connecting for a length of time, then gives up. I have managed to get the update tool pop up - so I'm not sure if thats an indicator of some internet connection or not (presumably it only generates the list of packages to update when it can connect to the net and see what updates are required...) I believe its also managed to get 1 or 2 ping packets through to the internet. I'm driving a belkin N-wireless USB adapter, N10117.
I two servers set up: 192.168.1.150 and 192.168.1.160 Initially, I want all traffic to be served by server 150. So for this purpose I am leaving the IPTables on .150 empty. At a point in time, I want to forward all incoming traffic to be served by .160 instead. I have accomplished this using these commands (on .150):
My problem is that if I have an open SSH connection to .150 (prior to adding the rules), the packets are still handled by .150 after adding the rules.. e.g. my SSH session stays active. I want these packets to be forwarded to .160, which would effectively disconnect the SSH session. I do not want the packets flat out dropped, I just want them forwarded on in whatever state they are in. If I try a new SSH session, it is properly forwarded to .160
i m using RHEL5 on my server machine and open suse 10 on my client machine.both system ping each other, firewall is off of my server machine,i put a file from my client to my server machine using scp command but ftp command is not working when i want to open connection i receive a message "connection refused".what can be the issue?
I am running Ubuntu 10.10, and I would like to use my computer to share the internet connection from an ethernet port. For example, I would like to set up my computer as a wireless access point so I can create a network that other computers can connect to for internet.
