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Monitoring Internet Traffic in Switched Networks These days, the majority of local networks are switch-based. Unlike a hub, a switch, when it has received a packet from some port, retransmits it only to one port, where the recipient computer is connected to it. Switches maintain a table of MAC addresses and ports associated with each of those addresses ...


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Turns out my ethernet card has different mac address (I didn't know that's possible, call me noob). There's a shared router with whitelist, and apparently it doesn't let me through when I use eth.


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Assuming the bridge is working[1], you have the two devices connected together at layer two (MAC layer); are both sides on the same layer three (IP) network? Can you describe how "the user application [is] connected to tap0"? (I'm assuming the router in GNS3 is attached to tap1 via a "cloud".) @Celada, Mac OS X networking is the same as FreeBSD, on which ...


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When you read from a socket (or pipe or other asynchronous source), you can choose what happens if there's no data immediately available. Either you can have the read wait until some data arrives (blocking mode), or you can have it return immediately with an error (nonblocking mode). The error it returns in the second case is EAGAIN. So the EAGAIN error ...


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From what I have gathered from experimenting and reading, I agree with uther that Network Manager seems to load by default, but the network service does not. When I recently had a VM host starting up without eth0 showing up in ifconfig output, it was because I had Network Manager running, network not running, and NM_CONTROLLED=no in my ...


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1: You should't use anonymous ports (a.k.a. ephemeral ports) to implement a UDP or TCP service. By default, these ports are in the range 32768 - 65535. # ndd /dev/tcp tcp_smallest_anon_port 32768 # ndd /dev/tcp tcp_largest_anon_port 65535 2: Unless your service is running as root or has the required RBAC privilege, you shouldn't use a privilege port, by ...


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You can use 1-65,535 ports on your system in which first 1024 are root privileged. So Instead of finding the free port, you can get list of used ports using below command netstat -tunlep | grep LISTEN | awk '{print $4}' Then you can use any port from 1-65535 except those ports.


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As far as I'm aware of sed cannot do calculations on numbers, I would use awk $ awk -F'.' '$1~"IPADDR"{$NF++;OFS="."}1' file DEVICE=eth0:1 NETMASK=255.255.255.0 IPADDR=10.2.7.149 BOOTPROTO=none ONBOOT=yes DNS1=10.2.53.150 PEERDNS=yes DNS2=10.2.53.250 GATEWAY=10.2.7.1 TYPE=Ethernet USERCTL=no IPV6INIT=no Include this into a loop of files to be changed. ...


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I don't know if I've understood you correctly. Does this do what you want? Bash: [root@domain]:test # IP=120 [root@domain]:test # for i in {1..50}; do > echo "IP=10.11.11.$IP > NETMASK=255.255.255.0 > DEVICE=eth0:1 > ONBOOT=yes > DNS1=10.2.53.150 > PEERDNS=yes > DNS2=10.2.53.250 > GATEWAY=10.2.7.1 > TYPE=Ethernet > USERCTL=no ...


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With perl : $ perl -ne ' s/^(IPADDR=10\.2\.7\.)(\d+)/$2 < 255 and sprintf "%s%s", $1, $2 + 1/e; print ' file Output: DEVICE=eth0:1 NETMASK=255.255.255.0 IPADDR=10.2.7.149 BOOTPROTO=none ONBOOT=yes DNS1=10.2.53.150 PEERDNS=yes DNS2=10.2.53.250 GATEWAY=10.2.7.1 TYPE=Ethernet USERCTL=no IPV6INIT=no You can add -i switch to modify the file ...


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NAT (Network Address Translation) has nothing common with the goals you described. Correspondence between IP and MAC addresses is kept using mechanism named ARP (Address Resolution Protocol) for IP version 4 and Neighbour Discovery for IP version 6. In rare circumstances, you can maintain the neighbour list manually, but it's rarely needed. For assigning IP ...


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You're lacking the APN in the --wds-start-network option. You wouldn't need it if you were in a CDMA/EVDO network, but it is (usually) required an explicit one in GSM/UMTS/LTE. Once QMI WDS Start Network returns with no error, just try to run dhclient in the WWAN interface.


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They are not two approaches. In one case you use bridge-utils directly (which is a temporary configuration change) in the other case (permanent configuration change) you use them indirectly via the network scripts which parse /etc/network/interfaces.


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Technically they should both use the same way of resolving addresses, however ping is likely not going to try resolving IPv6 addresses at all (AAAA records) and query directly A records as it's an IPv4-only tool (ping6 does IPv6 ICMP requests). A configuration issue I've seen in some load-balancing DNS servers backed by named (the same should apply no mater ...


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You solve this problem by installing a proxy on A which will listen for B/SecretPort and forward it to SomeServer. Answers picked on A with SecretPort are forwarded to B.


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Per your comment: @Marki - computers A and B are on the internet. When they go to someserver.com, they always do so from my Linux box (e.g. specific routing). A and B cooperate. On occasion, we want computer B to go to someserver.com without someserver being aware requests are coming from a different machine. Am I missing something here? If ...


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https://www.kernel.org/doc/Documentation/networking/bonding.txt fail_over_mac Specifies whether active-backup mode should set all slaves to the same MAC address at enslavement (the traditional behavior), or, when enabled, perform special handling of the bond's MAC address in accordance with the selected policy. Possible values are: none or 0 This ...


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Don't make any changes to the config files which do not reflect the current state of the system, otherwise the network scripts get confused when they read the config to stop networking, but the config files don't match what's actually configured. The correct way to change network config files is first stop networking (service network stop), then make your ...


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Make sure you are part of the KVM group also. The recommendantion is to make every virtualization things (network configuration, firmware access, qemu configuration) available for the kvm group.


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For general access, you'll have to use MASQUARADE / SNAT (depending if your IP address on C is dynamic or static). So let's say current situation is your computer A has static IP address a.a.a.a, and your computer B has static IP address b.b.b.b. Both have default gateway to computer C. And Someserver.com has static IP address r.r.r.r and secret port is ...


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Well...you could do just that. Give the DomUs all static IPs and be done with it. You'd then want to have Dom0 act as a gateway router and update everyone's routing table on the 172.16.1.0/24 to talk to go to Dom0 if they want to access 192.168.0.0/16. This is a messy question and a messy solution. Your wanting to put two separate networks on the same ...


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When I changed the line auto wlan0 to allow-hotplug wlan0 in my /etc/network/interfaces file, it just worked. The answers to this question helped me.


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I removed isc-dhcp-client and switched dhcpcd and the network/interfaces hostname now works.


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Assuming, IP_EXT1 and IP_EXT2 are the external IP addresses for respectively machines #1 and #2, and IP_INT1 and IP_INT2 their respective internal IP addresses. IP_EXT1 and IP_EXT2 are in fact addresses of the routing machine, either aliases for the same network interface or two distinct interfaces. Then, the iptables configuration on the routing machine ...


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An alternative to using iwconfig and wpasupplicant "by hand" is to edit /etc/network/interfaces and add a stanza like iface wlan0 inet static address 192.168.x.x netmask 255.255.255.0 gateway 192.168.x.1 dns-nameservers 192.168.x.1 wpa-ssid mynetwork wpa-psk 4bare2011 or iface wlan0 inet dhcp wpa-ssid mynetwork wpa-psk ...


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Your wifi network most likely uses WPA authentication, not the obsolete and insecure WEP. For WPA (WPA2, etc...), you cannot set the key directly using iwconfig because there is a higher level protocol that must be observed. For WPA, you need to run the wpasupplicant software. Most operating system distributions provide a supported method for correctly ...


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try this setenforce 0 iptables -F then try to ping your public ip to see your public ip try ifconfig or go to Google and typ what is my ip then you see your ip and try to ping . and now you can remotely login using ssh, telnet., etc internet....... and sorry if i m worng......


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I found the problem. The problem was the driver that had some bugs. I downloaded the most recent version of the drivers for my ethernet card (Intel® Ethernet Connection I217-V) embedded in the motherboard (GA-Z97N-WIFI) and installed it. It works with no problem.


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Gateway of your server (in the 192.168.1.0 network) most likely doesn't know about the existence of the 10.8.0.0 network. Either add a route in the router so it redirects those packets to your server or use NAT on the server for packets coming from the tun interface.


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CNAME is used to create aliases to the same destination, however your domains (mysite.net and www.mysite.net) do not share the same destination. You must set up two A records: $TTL 1D $ORIGIN mysite.net. @ IN SOA ns1 admin.mysite.net. ( 0 ; serial 1D ; refresh ...


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Try: sudo apt-get update sudo apt-get install linux-headers-`uname -r` dkms build-essential bcmwl-kernel-source reboot See: https://answers.launchpad.net/ubuntu/+source/gnome-nettool/+question/252499


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You can install just the telnet package and have telnet client functionality. Alternately, you can use the nc command to test port connectivity if you'd rather not mess with telnet at all.


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Normally, the NIC will only interrupt the CPU if it needs to send the received packet to the system. In non-promiscuous mode, this would only be for packets addressed to its MAC address, the broadcast address ff:ff:ff:ff:ff:ff, or a multicast address to which it has been subscribed. It also does validation before sending the packet to the CPU: the normal ...


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From askubuntu.com @SuB have the answer. Answer modified to suite centos. Those counters are kept by the kernel, so your answer depends on how your network card driver is built. Two possible choices: Kernel module Inside the kernel If it is second, you can not reset counters. If it is first, you can do it by uploading the module from the kernel and then ...


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lspci doesn't show your network adapter. That means it isn't connected to the PCI bus. All PCI peripherals appear in the lspci output, regardless of whether you have a driver for them: it's a PCI feature. The text descriptions (like “Intel Corporation 82573L”) are from a database, but the controller would at least appear as “Ethernet controller: Device ...


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Your commands do no sort of "server interaction", at least not in what most people would consider. They simply display networking information and the current kernel information. In windows you can run ipconfig /all and a similiar command for uname would be systeminfo You could always install cygwin and have those exact commands at your fingertips.


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I had a similar problem, but the solutions here didn't work for me. I had this output from mount: //10.0.0.173/e$ on /mnt/mount_tmp type cifs (rw,mand) I tried the mount --move and the umount -a -t cifs alternatives, didn't work. I tried unmounting both //10.0.0.173/e$ and /mnt/mount_tmp, nothing worked for me. I also tried the -f and -l proposed, to no ...


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Most likely the device isn't listed in /etc/network/interfaces try adding iface eth1 inet dhcp to that file


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Try to narrow down your problem. check dmesg to see if there's something obviously wrong. Does the internet connection come back up? if not, how do you get it back up? Are you using dhcp or static ip? is it configured on /etc/network/interfaces ? if so, post your config


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If you read /etc/sysconfig/network-scripts/ifup-eth you'll see that networking uses DHCP if BOOTPROTO is set to dhcp or bootp, otherwise it's not used: if ["${BOOTPROTO}" = "bootp" -o "${BOOTPROTO}" = "dhcp" ]; then DYNCONFIG=true Further down, if DYNCONFIG is not null (and dhclient is available) then the scripts attempts to use DHCP otherwise static IP ...


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Lots of good answers here, but wanted to throw in my usual approach: The simplest solution is to get the route for a public internet address: $ ip route get 1.1.1.1 | grep -oP 'src \K\S+' 192.168.0.20 Another solution is to get the default gateway, and then get the IP addr used to communicate with that gateway: $ ip route get $(ip route show 0.0.0.0/0 | ...


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If what you want is the IP address assigned to the default interface (which is what I understood from the comments under the question), using the Swiss army knife of network setup (ip) should be enough: $ ip route | grep '^default' default via 10.176.143.1 dev eth1 metric 203 $ ip addr show eth1 4: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 ...


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p1p0 is a interface wich name was given by BIOS. More information at : http://linux.die.net/man/1/biosdevname and the vibr0 it's a virtual bridge. More information at : http://askubuntu.com/questions/246343/what-is-the-virbr0-interface-used-for


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Here's another slightly terser method using procfs (assumes you're using Linux): default_iface=$(awk '$2 == 00000000 { print $1 }' /proc/net/route) ip addr show dev "$default_iface" | awk '$1 ~ /^inet/ { sub("/.*", "", $2); print $2 }' This returns both the IPv4 and (if available) the IPv6 address of the interface. You can change the test if you only want ...


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Here's what I wrote: Get the default interface from the "route" command. It will print out which interface is the "default". For my host, I need to get the last column of the default line. [root@pppdc9prd3ga mdesales]# route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.4.0 * ...


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Fundamentally, your problem here is that the bandwidth on your downstream connection (eth0) is higher than the bandwidth on your upstream connection (wlan0). To solve this, you need to throttle the speed on eth0 to something below the speeds of wlan0; I have used Wondershaper for this sort of thing.


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Do you want to detect an nmap scan as an academic exercise, or are you trying to actually detect attackers who are performing a port scan? The latter can be extremely difficult, since an attacker can slow down the scan and/or distribute the scan across a number of clients in order to defeat any heuristics that you might implement. So, be aware that if this ...


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Have you looked at the emerging threats ruleset? Specifically their scan rules? You will never detect detect scans with 100% accuracy. Generally speaking, thresholding is useful. On border firewalls on a large network, I look at e.g. number of distinct hosts contacted by a some remote host over a certain period. On a single host, the number of distinct ...


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The passive operating system identifier, p0f, can identify nmap scans, at least of some types. Bear in mind that nmap can do a lot of different types of scans from simple ping scans to very exotic. What you're asking might not be 100% possible.


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Configure sudo to allow you to run the command without a password: As root: # visudo append the following: <username> ALL = NOPASSWD: netctl start network, netctl stop network where <username> is your username (without < and >) or ALL to allow everyone to do this. You can also stipulate a group by preceding it with a % (eg %admin).



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