I have a system running 11.04 and it is dropping packets on the hardwired ethernet interface to other systems on the LAN, only in the inbound direction. It drops packets every 5 seconds. I verified this with iperf. Outbound packets pass with no problems. The network card in this system is a Broadcom Corporation NetXtreme BCM5752
View 9 RepliesI've got an odd one, running the CentOS 5.3 kernel, I'm experiencing lost packets on one of the two NICs when tested with ping. In this particular case, it's the internal NIC that causes the problem, pings from the CentOS machine to the public network over the external NIC never loses packets.(internet)<-->CentOS<--> (LAN) <--> desktop
- CentOS can ping the internet with no packet loss
- CentOS loses packets when pinging the desktop(s)
- Desktops lose packets when pinging the CentOS box
- Taking the LAN switch out of the equation still results in lost packets
- When the LAN NIC on the CentOS box "acts up", all desktops start losing packets
I've swapped out the NIC a few times for different makes/models, and I'm still getting lost packets to/from the internal network. So, I'm thinking that there's something squirrely going on higher up in the network stack. But evidently, not enough to log anything to the console or into the log files.At the moment, I'm leaning towards it being an issue with the nForce 750a SLI chipset. But it's odd that it only affects the LAN card and not the WAN card. I've even swapped the positions of the two NICs, and the problem persists on the LAN card.The other possibility is that iptables is eating packets silently, but in a random fashion.
Pinging out from my netbook (over wifi, to any host) gets ~0% packet loss. Pinging into it (from any host) gets about 50% packet loss.
The router is a Dlink-DIR615 (rev d, running DD-WRT v24-sp2) but all other hosts on it ping eachother fine. I've tried changing routing, disabling IPv6, using older kernels and using wicd, all with no luck. The wireless connections is at 100% most of the time. This could be a new problem with Maverick, but I may not have noticed it before. I believe this is causing web browsing to be really slow and causing SSH timeouts.
I haven't tried madwifi drivers or nsidwrapper yet.
Edit: just booted into Windows and it has the same problem. Could it be a hardware issue? Also tried with a static IP, with no change.
Strangely, a normal ping gets 50% packet loss, but ping -A gets < 1% loss.
Edit 2: no packet loss at all on eth0.
Code:
# uname -a
Linux hulbert-laptop 2.6.35-23-generic #36-Ubuntu SMP Tue Oct 26 17:03:18 UTC 2010 i686 GNU/Linux
Code:
# ifconfig wlan0
wlan0 Link encap:Ethernet HWaddr 00:25:d3:1a:bc:4b
inet addr:192.168.0.102 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::225:d3ff:fe1a:bc4b/64 Scope:Link
[Code]....
I have had this issue for a while on my centos 5.4 dedicated server with 1and1. If I reboot my system, my connection starts and then drops in about 10 seconds after the system has booted.I connected through the serial console and noticed there was only one thing that seemed suspicious while booting. named could not start for some reason. So my question is - are these 2 problems related? If not, what could be the reason for my connection to drop?At the moment the only way of getting the connection back up is by running dhclient. This works until the next reboot.
View 1 Replies View RelatedI have had this issue for a while on my centos 5.4 dedicated server with 1and1. If I reboot my system, my connection starts and then drops in about 10 seconds after the system has booted. I connected through the serial console and noticed there was only one thing that seemed suspicious while booting. named could not start for some reason.
So my question is - are these 2 problems related? If not, what could be the reason for my connection to drop? At the moment the only way of getting the connection back up is by running dhclient. This works until the next reboot.
I think "Absolute Beginners" is not the best place for it to get an answer. It might take a while to get moved. Forgive me, but I might loose my borrowed machine at any moment so no connection at all then and I'm in a place where I have no idea how to find a cafe.I've attached diagnostic output following someones help to a 10.04 user.[URL]
View 7 Replies View RelatedI've a ssh server on FEDORA 12. It was going well but now it's overloaded with ARP traffic and is unable to run ssh. normally i'm getting about 150 packets in just 3 second
View 1 Replies View RelatedI just performed a clean install on a desktop (older IBEX model) that is connected directly to a Cicso router; this is a DSL service. I configured the Network during the install, and all went well, the installation script downloaded many software modules, I was able to set up my mail accounts, etc. Now, if I suspend this machine and log back on I notice that I am no longer connected to the Network. Clicking on the Network icon brings up the configuration pane, and the original network appears to be there, but I cannot figure out how to make it reconnect without rebooting.
View 3 Replies View RelatedI'm having issues with my wired network. After about 5-10 minutes of turning on my machine, the network will drop out. Sometimes rebooting my pc or router will fix the connection, other times it will have no effect. Also, sometimes the connection will completely disconnect, other times it will appear to be connected (i.e. the network icon will indicate that there is a connection), but trying to ping a remote server or the router will fail.
This problem first showed up on Fedora 11 64, however I've just installed Fedora 13 64 and that hasn't helped. I'm using a brand new NIC (I've tried using the onboard NICs). The machine also has Windows 7 installed, which is able to connect just fine. Apart from changing NICs, the only other thing I've tried is switching from dhcp to a static IP address.
I can connect to the wireless at my school, but the connection drops frequently and regularly. Network Manager still shows bars indicating the network strength and shows that it's connected to the network in the dropdown. Selecting the network again causes it to indicate that it disconnects and reconnects. At this point I have wireless until the connection drops again. Possibly relevant details: This is the Purdue PAL2.0 network, which can be tricky to connect to, particularly for Linux users. It's a hidden network using WPA2 and PEAP. My computer is a Dell Inspiron 1420n laptop, circa August 2007.
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I am not a networking expert by any means (in fact I have never taken a networking course), but I have taken several security courses, and generally we wind up discussing replay attacks. For example, the Needham-Schroeder protocol (using symmetric-key cryptography anyway) is flawed because it allows for replay attacks, and I understand why.
I guess my question is actually how someone would perform a replay attack. I know I can sniff network traffic by downloading wireshark. I also have downloaded winpcap and npg on my WinXP virtual machine. I'm trying to use this guide to help me, but I'm quite lost:[URL]What I did was to post a "link" to my facebook profile and I sniffed the traffic using wireshark. What I would ultimately like to accomplish is to copy that packet out of the wireshark output, and then use a tool like npg to transfer the raw packet back to facebook, which should result in a second, redundant post. I just can't figure out how to do that.
I'm pretty sure this should be possible. Facebook only uses an SSL session for authentication during login. After that, the information is just sent in the clear, so I'm pretty sure this should be possible.Can anyone explain how to do such a thing? It would really help my research paper that I'm working on this semester if you can. As of right now the attack we are trying to demonstrate/defend against is using a Windows VM, which is why I'm using winpcap/npg. The attack is actually possible using just about any OS (depending on the exploit used), but our POC is Windows only at the moment
I'm using madwifi linux driver (ath1) in monitor mode to capture some wireless traffic. I can see that all wireless traffic is coming well through the wireless interface (checked using TCPDUMP). What I want to know is how I can forward the captured wireless packets to a different Ethernet interface (e.g. eth2) in the same machine to send those captured packet out to a different computer.
I set 1 for /proc/sys/net/ipv4/ip_forward
for iptables, I tried this rule: iptables -A FORWARD -i ath1 -o eth2 -j ACCEPT
However, I coudn't read any packet from eth2 via TCPDUMP.
I am running into trouble while trying to set-up a iptables routing policy. I have two machines on the same sub-network (xxx.xxx.153.0). One of the machines is used as a default gw for the other (xxx.xxx.153.250 is a gateway for xxx.xxx.153.142 and xxx.xxx.153.254 is a gw for xxx.xxx.153.250). There is no explanation for why the xxx.xxx.153.250 is in the middle -- xxx.xxx.153.142 can go straight to xxx.xxx.153.254, but is is like that for now.I am trying to find an iptable rule to be executed on the xxx.xxx.153.250 machine to route the packets.
View 3 Replies View Relatedi 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 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?
View 1 Replies View RelatedI'm sniffing network packets in ubuntu, I need to write these packets as raw bytes to memory but libpcap give packets in its special format. how can i save and recover packets in byte format?
View 2 Replies View Relatedi need to write a program in c that can sniff packets from Ethernet and distinguish RTP packets from Non-RTP packets, i have no idea what should i do
View 9 Replies View RelatedBasically upon logging network manager will connect to my network, and most of the time it will only last 20 seconds or so before it disconnects and tries to reconnects, this tends to go on for quite a while. Logging off and logging on over and over worked once, for this post I opened pages between the 15 seconds that i was connected and after 20 minutes it has remained connected (every time it stays connected for longer than 5 minutes it will never disconnect again) I followed the HOWTO thread so forgive me if most of this information is useless
1 ) Machine Brand and Model (Laptop): Asus 52jr is the model number
2 ) Wireless Brand, Model and Wireless Chipset:
03:00.0 Network controller: Atheros Communications Inc. AR9285 Wireless Network Adapter (PCI-Express) (rev 01)is what I found from running lspci
3 ) check interface:
Code:
wlan0 Link encap:Ethernet HWaddr 1c:4b:d6:5c:61:8b
inet addr:192.168.1.101 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::1e4b:d6ff:fe5c:618b/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
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I'm currently on F11, and experienced problems with Network Manager. Whenever I to connect to a network, wired or wireless, it just seems to try to connect, and then after 2-3 seconds, it just reports "Disconnected"..
Then I switched to network, and both wired and wireless works. so I don't think there is any driver or hardware issue...
Does anyone have any idea of this problem? The network manager have worked on the live CD version ( before installed to HD).
I have a Fedora 12 box, which works absolutely fine in a fastweb wlan. However, if I connect to another wlan where I need to link to a wireless access point cabled to the ISP modem/router, networkmanager shows the connection is ok, but...
1) I only can browse internet (es:www.google.it) for a few seconds after the connection is established, thanfirefox goes "Impossible to reach the server"
2) the same behaviour is confirmed by ping
Code:
[Adriano@localhost ~]$ ping www.google.it
PING www.l.google.com (209.85.135.106) 56(84) bytes of data.
64 bytes from mu-in-f106.1e100.net (209.85.135.106): icmp_seq=1 ttl=49 time=138 ms
64 bytes from mu-in-f106.1e100.net (209.85.135.106): icmp_seq=2 ttl=49 time=127 ms
[code]....
EDIT: There is a win box in the same net that is working fine.I see in the router config that ARP for the working machine is "complete", while for the Fedora one is "incomplete" Nothing changes configuring a static or dynamic IP address for the Fedora box I had a previous Fedora 11 installation on the same machine that now gives troubles, and it worked fine. But I can't tell if it's a software problem because my ISP seems to have telnet-ed the router, changing it's firmware (and maybe it's config). Shame on they.
I have windows 2003 server which i stored some important data that the workstation will connect it or access by thru network connection...
My current setup is: i have a linux distro i used mandriva 2009 and i installed samba...if i used windows to browse in network i can see the name of the pc of linux and i can able to access the linux shared folder.
My problem is if the linux try to access the windows 2003 thru network it seems to be nothing happened coz everytime i click the linux network it shows me a blank after a few seconds...
I really dont have idea if there is any requirements for the windows.
I really want to implement the linux workstation but i still have a big problem issue in networking.
I've troubles getting my new Sweex wireless 300N USB adapter to work. Tried searching in several directions (see closed thread). Further investigations shows however it is caused by the NDISGTK wrapper for Windows drivers. Can anyone tell me whether Sweex is shipping a faulty driver (it is the latest available) or it is a fault in ndisgtk? Or maybe I'm doing something stupid myself, which I do not find completely imagenary below some more detailed information on my findings: Started with network off and examined the networkstatus
Quote:
tpeelen@CC-desktop:~$ sudo lshw -C network
*-network DISABLED
description: Ethernet interface
product: RTL8111/8168B PCI Express Gigabit Ethernet controller
[code]....
Looking at the output of netstat, I'm not seeing a definitive way to tell which torrent connections are clients reaching in to my machine vs my machine reaching out to the world. Is there a clear way to determine which is which?
View 1 Replies View RelatedI have installed apf-9.1.7 on linux,after installation inbound activites stopped as per the rules defined.I have added port 20,21 (ftp) in IG_TCP_CPORTS,but still ftp is not working from other Pc.
View 1 Replies View RelatedI have a hardware device with two ethernet ports, eth0 and eth1 running Centos 5. Basically my goal is to forward packets from eth0->eth1 and eth1->eth0 as well as get a copy of these packets for analysis. If I set IP routing to do the forwarding then I won't get a copy of the packets for analysis.
View 3 Replies View RelatedI'm facing an odd problem with a fresh install of OpenSuse 11.4 on a Dell PE-2950, using NIC Broadcom BCM5708C (rev 12) NetXtream II. Driver's are up to date. I'd installed vsftpd and configure it. I can connect from anywhere in the network where I setup this Server. The odd problem is that when I'm sending a big file (5.5 GiB for example), from another PE-2950 server (Windows Server 2003 64 bits R2) with another BCM5708C nic, the speed of the transfer starts at 90 MiB/s approx. but after 30 seconds , it drops to 15 MiB/s and never raise again. Driver's are up to date too.
However, from another Server in the network, a Dell R710 with SLES 10 SP3, the transfer speed is at 90-100-110 MiB/s all the time. The switch is a HP Procurve 2910al-24G, with all ports at gigabit speed. I'd tried with different FTP clients in Windows: WinSCP and the Windows's ftp client, but the result is the same: speed falls down after 30 seconds approx. using the Windows-Box.
Installed Fedora 12 recently.
For some reason, my network connectivity drops out randomly. This has happened between 5 minutes to 1 hour of booting and logging into the machine.
When the internet does work, its great, and super fast !
When it drops out, Internet stops working, cannot ping to external site and I cannot ping my router 10.1.1.1
I have onboard realtek network ports on my motherboard.
I have an Ubuntu-based fileserver, which I have set up and works fine for 5 computers (Windows & Linux based). I have one computer, on Windows, which when I map as a network drive it works and I can transfer small files using the USB adapter. However, when copying over a large file, after 2 mins or so it comes up with the error "Specified network name cannot be found". However when plugged in using Ethernet, it will work fine.
What is even stranger is when I set it up as an FTP server rather than SAMBA, it will happily transfer a 4gb file on the USB adapter, which possibly knocks out driver issues (I have tried 2 different drivers, am currently using Linksys one from website - WUSB300N) AND perhaps the issue lies on the Linux server side with setting up the SAMBA server? However I do have another one of these adapters that works fine, but it is on WIN XP HOME with a custom network logon script (as HOME won't remember passwords after restart). BUT it does work on another computer with XP PRO as network place, so I tried network place on this one, and it still doesn't work.......
I'm using Scientific Linux on a laptop, connecting to a debian server on my LAN via a basic BT HomeHub router. When starting a file transfer with ftp or rsync from the laptop my connection is dropped, every time, after a couple of seconds. I have to reset my network adaptor and restart my network manager (wicd in this case) in order to get network connectivity back. I had a very similar problem before - [URL]. On this occasion my workaround was to replace NetworkManager with yast. I am now using SL though so no yast available, and I am not using NetworkManager any more anyway.
View 3 Replies View RelatedI am using vnuml to test a network project. I have one Ethernet card on my ubuntu 9.10( eth0) with network 10.1.0.0/16, and creating a tap0 with subnet 10.4.0.0/16. Now the problem is how to work them together, such that packets from one interface goes to other one?
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