Debian Configuration :: Network Malfunction After Possible Ping Attack
Apr 8, 2010
I would like to ask something. Today my network Internet access suddenly slowed down, after inspecting the problem the hard way we disconnected one of our servers(ip=190, debian squeeze) from network and the network was alright again. When we plugged it back in, following symptoms were observed: computer 190 pinged gateway app. each 6th time. gateway(debian lenny) pinged computer 190 app each 6th time whole network Internet access was slowed down, local network functioned just fine
While pinging themselves, i ran iptraf on icmp packets on gateway and I saw what i thought was ping attack, lots of echo request coming from external address to computer 190. Blocking that address in iptables didn't help but restarting the gateway did, network Internet conenction is at full speed and gateway and computer 190 ping just fine.
My question is, what steps should I undertake in similar case (it's second time in 2 months) - to debug similar problems. Is it even possible for ping DOS to this kind of damage?
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Apr 6, 2011
I have a debian server installed with a static ip. Now i am able to ping my ip, but when i try to configure a domain name with the nameserver as my ip, i am not able to ping the domain name
eg:
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Mar 13, 2010
i am running debian testing and the last few days i was trying to ssh to another pc on my network and i was getting an error like there was no machine with that ip! then i tried pinging to it with no luck! ARP was the only tool that returned the MAC address of the machine and that is strange i think. i realised then that i could only ping the gateway and localhost (127.0.0.1 not my ip). after editing my /etc/hosts, i could ping my ip as well. what is so wrong? here are some useful things:
my new /etc/hosts:
jack@debian:~$ cat /etc/hosts
127.0.0.1 localhost
127.0.1.1 debian.local debian
[Code].....
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Jan 23, 2010
I recently did a clean install of Debian 5, and a backup program called BackupPC. Both machines are on a small local network served by a router. Both machines have statically mapped IP addresses, done by the router via matching MAC addresses in a table of corresponding IP addresses (192.168.0.2 (HP-PC-XP), 192.168.0.3 (Debian). I configured Backup PC correctly (I think)...Upon running Backuppc, the first thing it tries to do when its time to run a backup is to ping the machine to be backed up. The name of the PC is stored in a backup pc config file. (I believe BackupPC does a DHCP request with the machine name to get the ip address, but not sure). Running the backup results in BackupPC tells me that it can't ping my xp machine. If I open up a terminal window in debian, i can successfully ping my xp machine when i use the ip address. 92.160.0.2 If I ping using the host name of the xp machine (e.g. HP-PC_XP), the ping command displays some ip address i've never seen...something like 63.123.155.104....how is it getting that and how can it be corrected?
I recall that nslookup looks at the local hosts file first to resolve the name....i look in my hosts file and found no such address (only contained localhost)....now what?
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Aug 27, 2015
I've been using Debian for about 6-7 months now. I've had a bit of a major networking problem for the past 4 months or so that I've been trying to fix - specifically, it started when I upgraded to Jessie. I can connect to wifi just fine, and sometimes I can even use the internet for brief periods of time (exceedingly rarely). Then... nothing. No network access, period. I can't ping any outside servers, I can't ping other computers on my network, and I can't even ping my router. Pages I try to load just stay "connecting" for all eternity, network printing fails, and so on.
So after four months of searching online (I've read through way more wireless documentation than I care to say), I finally gave up and admitted that maybe I screwed something up during upgrade to Jessie (as a matter of fact, I did, I had to do the upgrade in two increments [somehow] because my root partition was too tiny by mistake) and I did a clean install. Since I had /home on a separate partition, I was able to keep all my user files, but all settings regarding networking were wiped. So after installing firmware-iwlwifi so I can use my wireless card, I tried connecting to wireless! Success! Then I tried connecting to the internet... success! Briefly. The next morning I tried using the internet again, and it failed in exactly the same pattern as before.
I don't know much about what's going on here, but here's what I do have available:
I do have to use firmware-iwlwifi, which I installed by doing apt-get install firmware-iwlwifi. I don't think it's an issue with the wireless card itself (hardware-wise), the laptop dual-boots Windows 7 (that I never use anymore), and Windows 7 is able to connect to the internet just fine. Connecting directly to my router by ethernet cable works fine, I have perfect internet/network access then.
I can confirm that my laptop is receiving an IP address and that it is using ARP correctly to get the MAC address of my router (I confirmed this by doing the arp command, it has the MAC address correct, I checked from another computer with my router's config page) All other computers on my network work perfectly with my router. To confirm the router/its configuration isn't at fault, I did a full factory reset of the router, but to no avail.
Out of curiosity I tried installing Wireshark (using an ethernet cable to download it) to monitor what happens when I try to access a webpage. I'm no expert on networking, but I noticed something out place when I compare a capture from the affected computer to a capture from one operating normally - there are a lot of STP packets showing up. I did some checking around, it looks like STP is involved in bridging and more complex networking setups (involving switches, for example)... but it shouldn't be found on a home network, especially where there's no bridging whatsoever. These STP packets don't show up on packet captures done from any other computer. I've attached a packet capture from the affected computer here, since the forums won't let me attach a .pcapng file.
Here's the output from a few commands I ran during past troubleshooting sessions:
Code: Select allsudo ifconfig
eth0   Link encap:Ethernet HWaddr e0:db:55:b5:fe:06Â
     UP BROADCAST MULTICAST MTU:1500 Metric:1
     RX packets:12455 errors:0 dropped:0 overruns:0 frame:0
     TX packets:7781 errors:0 dropped:0 overruns:0 carrier:0
     collisions:0 txqueuelen:1000
[Code] ....
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Oct 13, 2010
I have a very strange problem.ometimes, yes sometimes not all the time, I get a Destination Host Unreachable when I ping a computer on my network. If I switch to root using su I can ping that same computer. Here is a screen shot:
joseph@laptop:~$ ping 192.168.1.14
PING 192.168.1.14 (192.168.1.14) 56(84) bytes of data.
From 192.168.1.9 icmp_seq=2 Destination Host Unreachable
[code]...
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Feb 15, 2011
Just installed squeeze and noticing slow responses to ping. Ping with -n is fine, and as expected. Ping without -n is very slow to appear on the screen.
ben@WOPR:~$ ping google.com
PING google.com (74.125.230.114) 56(84) bytes of data.
64 bytes from 74.125.230.114: icmp_req=1 ttl=54 time=26.2 ms
64 bytes from 74.125.230.114: icmp_req=2 ttl=54 time=25.9 ms
64 bytes from 74.125.230.114: icmp_req=3 ttl=54 time=29.3 ms
64 bytes from 74.125.230.114: icmp_req=4 ttl=54 time=25.5 ms
^C64 bytes from 74.125.230.114: icmp_req=5 ttl=54 time=25.8 ms
--- google.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 20199ms
rtt min/avg/max/mdev = 25.514/26.569/29.308/1.399 ms
ben@WOPR:~$ ping -n google.com
PING google.com (74.125.230.115) 56(84) bytes of data.
64 bytes from 74.125.230.115: icmp_req=1 ttl=54 time=25.6 ms
64 bytes from 74.125.230.115: icmp_req=2 ttl=54 time=26.0 ms
64 bytes from 74.125.230.115: icmp_req=3 ttl=54 time=26.8 ms
64 bytes from 74.125.230.115: icmp_req=4 ttl=53 time=21.5 ms
^C
--- google.com ping statistics ---
5 packets transmitted, 4 received, 20% packet loss, time 4006ms
rtt min/avg/max/mdev = 21.540/25.042/26.859/2.064 ms
I've tried disabling ip6, disabling avahi and adding options single-request to my /etc/resolv.conf - problem remains. If it helps when installing Squeeze was prompted to install firmware-realtek, which I didn't have. So downloaded onto usb from another machine installed once setup was complete.
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Jan 8, 2011
I have set up a MythBox on Debian Lenny. I have a wireless connection using a Belkin USB WiFi Device. I am using ndiswrapper, wpa_supplicant, etc. I am using a static ip address. I have internet access without problems. However, if I try to ssh in or even ping my mythbox inside my network there is no connection. I have never had to do anything special to ssh into debian in my network before. I am confused that I have an internet connection but can't get a ping reply.
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Feb 23, 2011
This applies to my 2 opensuse PC's, my Windows PC is fine.I can ping a hostname, say "PC1" but I can not ping PC1.domain.local (even the host PC can not ping it's own FQDN). When I ping just the hostname the ping stats even list the FQDN.Onto the next issue, since all my PC's, have the domain prefix domain.local, my Synology can not. I can ping it's IP and that is it. I can resolve it's name with nmblookup just fine tho and that is what is killing me. How is this not resolving.Even weirder, I can browse to "Synology" in Network Servers under places on the slab.
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Jun 16, 2009
My hard drive's file system has become totally mucked up. I had a few partitions on it, 0 is XP, 1 is vista, 2 is Debian, and 3 is the data. I know that it's this hard drive because when I disconnect it, any liveCD runs ok. After failing to boot puppy linux (liveCD), xp (bootmgr not found), debian (ended in kernal panic), I tried GPARTED. The xp and vista partitions are listed as existing, but they show a problem flag, gparted says they are corrupt, and they are not listed as having a start, end, or any data. However, the main data partition does list a start, end, size, and data space used.
I need to either format those or get into something that will let me access the data partition. Gparted either hangs on boot or doesn't recognise the mouse so I can't reformat the bad partitions. Are there any programs that will ignore the bad partitions and let me access the good ones? Any time I go into a linux distro it either ends up in kernel panic or the mouse doesn't respond. It's hard to explain. With GPARTED, sometimes it hangs at the third line, sometimes it fails at "mounting hard drives", and sometimes it makes it to the GUI but I can't use the mouse. Debian alternates between these as well.
If I keep trying it looks like I can boot, and it will recognise the partitions, but I can't use the mouse. I'm kind of familar with bash, is there a way to start up the terminal with no gui? If I could get a terminal up with a hotkey in the GUI or just start up from a terminal (no gui), I could type mv dev/sda3/ or whatnot. If I could get into a terminal of gparted I could format the bad parts of the drive to see if that would work. Otherwise it looks like I'm going to have to zero out the drive with the WD diag tool. The data isn't life or death, but it would save me some time.
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Sep 27, 2010
i have installed linux debian in my computer but i have aproblem , i have a ping only on my computer itself , not to gateway or other computers on my network .
Ip : 10.0.88.9
Gateway : 10.0.88.1
dns :10.0.88.7
note:when i have installed system i have no internet connection so it is not installed updates
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May 3, 2010
Quote:
The 605-page PDF document reads like a listing of the pros and cons for a huge array of defensive and counterintelligence approaches and technologies that an entity might adopt in defending its networks. Of particular interest to me was the section on deception technologies, which discusses the use of honeynet technology to learn more about attackers� methods, as well as the potential legal and privacy aspects of using honeynets. Another section delves into the challenges of attributing the true origin(s) of a computer network attack.
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Jan 29, 2011
I'm using debian lenny.When I boot with kernel 2.6.36, ping always respond with Network is Unreachable. But when I boot with kernel 2.6.26 it works. I can't even ping the dafault router of 2.6.26 kernel when I am at 2.6.36. Also, system/administration/network does not show any connections while it shows something at the other kernel.
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Apr 9, 2010
I need to learn how to analyze network traffic for attacks and while finding the attack seems easy in my case I need to identify what hes doing. I will be happy right now if you guys can answer my question. How to identify if an attack has brought the server down? I have packet captures of an attack in progress and I noticed that every now and then the attacker would do something weird and the server would start sending packets with just the RST packet sent in response. Normally I had been seeing the RST ACK flags set or the FIN ACK bits set to terminate a connection. So once again my question is how do I tell if the traffic indicates a server crash?
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Jul 9, 2010
Ive got a problem on my server ....installed Debian 5 , Webmin and than syscp settung up syscp ready ....
I try to ping "localhost" ansver ping: unknown host
I try to ping "localhost." there is a host with IP 127.0.0.1
I need it to change it in "localhost"
Is that the bind9 maybe?
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Mar 3, 2011
I was playing with my debian server when something went totally wrong while i was editing something on my network interface,i removed those crap that i wrote and left the network interface configuration as it was
Like for example after re-editing my network interface,it was like :
As i did a network restart, i get this error saying :
There is already a pid file /var/run/dhclient.eth0.pid with pid 2802 killed old client process, removed PID file.
What is this error and how can i fix it,because every time im re booting my server i lost my network config.
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Jul 15, 2011
I am using an virtual machine. where I need to ping from one machine to another. earlier I was able to ping. But after going to google.com once, I cannot ping back to this machine.
But if I gave ping -I eth1 <IP> then I can ping.
I cannot install any package, so tell me solution which includes not installing any package.
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Oct 24, 2010
I'm planning to use Debian as the OS for a firewall machine, which will sit between my internet connection and the rest of my computers. Now my network is all wired, no wireless whatsoever. I'm using the onboard the motherboards cat5 socket which seems to be using the VIA rhine driver and I'm also using a 3com 100MBps card.
I can list the machine spec if you want but it's nothing special, an old Athlon 64 rig with 1gb ram and an OEM motherboard, it all seems to work ok apart from the internet doesn't' seem to work. Lenny seems to detect both cards ok and I even used the net install CD and it managed to download everything using the 3com card.
The strange thing is when I'm in Lenny, I can't seem to connect. I can ping google, but when I try and view a webpage, the browser just sits there with a while screen... Could it be that using 2 network cards is confusing Debian? Right now I've only got the modem hooked up the the 3com card, and nothing connected to the onboard network card.
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Feb 14, 2011
I have a new install of Debian Squeeze from debian-6.0.0-amd64-kde-CD-1.iso but I'm experiencing problems with the wireless internet applet in the taskbar.When the computer boots, it doesn't connect automatically eventhough I have it set as such. I have to fiddle with it until I get the request from KDE Wallet Manager to insert the password to complete the connection. I didn't have this behavior in Kubuntu.
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Aug 29, 2010
I just installed open Suse 11.3, and I cannot SSH my school. Upon further investigation I could not even ping any machines outside my local area network. Ironically I could nmap machines outside my local area network.
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Jul 17, 2011
I installed openSUSE on one of my work system. The network port wasn't working when I was installing, but works fine now (checked in Windows). But for some reason, I am not able to configure the network. I used both Dynamic and Static IPs (both work fine in Windows) but still no go. I am using Yast Control Center for this purpose. I can't even ping the default gateway when I am using custom settings. When I use dynamic settings, it says Unreachable Network.
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Feb 13, 2011
I'm new to SuSe and lateley I was trying to establish a Network, when some weired problems occured. I was able to establish the network and i have connection to the internet. The suse-machine is rechable by ping from all the other computers in the network. If I'm tryiing to ping the other computers from the suse-machine, nothing happens. The router responds without packet loss, but every other ping occurs in:
From 192.168.2.6: icmp_seq=2 Destination Host Unreachable
From 192.168.2.6: icmp_seq=3 Destination Host Unreachable
From 192.168.2.6: icmp_seq=4 Destination Host Unreachable
From 192.168.2.6: icmp_seq=5 Destination Host Unreachable
I've been searching for some ideas to solve this problem but couldn't find any.
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Jan 18, 2010
I'm opening up Network and it asks me for the root password. I enter it and the program comes up. I enter a static address for both eth0 and eth1.
I don't see a Save button. Eventually I get out of the configuration tool. The next time I run the tool, my static addresses have not been saved.
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Sep 14, 2010
I've illustrated it on this picture, and hope to get the help i need to set it up... [URL]Thow it has to be furture secured, in that meaning it has to be abel to attach a eth2 on the main server, so i have 3 NIC's.Also, i want to have fully controll over ports, IP/MAC's and data overview (Such as a view of the files beeing downloadet/uploadet).
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Apr 9, 2011
I installed testing on my netbook with cd1. and too my suprise it didn't even include something as important as network manager. all i want to do is connect to my wired internet, install network manager, then install my driver for card. if i can just get wired working i will be homefree. the directions for installing my wire3less driver look super simple.
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May 21, 2011
I have a server and I have a few computers connected to it via a Airport Extreme. Using network cable. So when Im uploading,(ftp) IE using a lot of the network "space" the other computers on the network gets kicked out. So what is going on? My Airport Extreme is doing fine, but my other clients just get kicked out. If I pause the upload, everything is okay again. The whole network is 1 gigabit, clients, everything.
[Code].....
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May 25, 2011
I have a computer home that I use a web server and I had Lenny in it for about a year and didn't experience any problems. Recently I needed to update to Squeeze just to be able and use part of my server for a game(which I couldn't compile on Lenny). I renamed every "lenny" word in the /etc/apt/sources.list with "squeeze" and ran dist-upgrade. Everything seemed fine(minor some "link not found" warnings). I also had some minor problems with the mysql configuration after the update but I managed to fix them all. Then I noticed that after some hours(not sure how many) I can suddenly not reach my computer via ssh. Neither can I visit my website(even from the local network). The computer doesn't appear either in the router's "attached devices" list. My other computers have no problems so it can't be a router issue.Pinging from the server to the outside world doesn't work. I tryied "sudo /etc/init.d/networking restart" and that didn't do anything. The only way to fix the problem is by rebooting but then again after some hours the problem is still there. Do you guys have any idea what the problem can be?
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Jul 8, 2011
I try to use the "ping -a" command for getting an audible ping. But there is just silence The command "beep" works fine, so everything should be ok with the speaker (in the konsole).
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Aug 4, 2015
I'm trying to install using windows 7 on a 2010 macbook pro. Firstly the network configuration won't work and secondly the cd rom can't be detected. I've rewritten the usb drive several times with no joy.
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Aug 11, 2011
Some problems keep bothering me and dont let me use my debian sqeeze with joy.Im in network with no DHCP on. When installing i didnt configure my eth network card.After each restart i need to configure manually my eth because it loses it.
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