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1

when you set a bridge, it acts as a virtual switch for the VMs to plug into. The bridge IP will be used for the host, and the VMs plugged into the bridge, with IPs from the same subnet, will be on the same L2 domain. The other options are: NAT: In this case, the VM is running inside a virtual network inside the host, isolated from the public network the ...


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I know I'm supposed to give a long drawn out explanation, but Dan Seimon already has. In short txqueuelen is the buffer size. All the network packets fit in this buffer, whereas tx is the packet size of the IP Packet that goes in said buffer. That is if I understand that post correctly.


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You can either setup a DNS server and add an entry for your Pi's hostname + IP to it. All the systems that need resolve this hostname will need to make use of this DNS server. Your other option is to add an entry in your system's hosts file with an entry that specifies the Pi's hostname + IP address. 1.2.3.4 pi-host NOTE: Yes Windows systems do have a ...


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I'm assuming you are getting ping: unknown host www.google.com because your name resolution if failing because of the network connectivity issues mentioned below. However, you probably want to double check that this isn't just a DNS issue by pinging an IP address. From what you've provided, it looks like you haven't added a physical interface to the ...


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All you need to do is ip link add link eth0 address 00:11:11:11:11:11 eth0.1 type macvlan then turn on the virtual network interface ifconfig eth0.1 up and then optionally acquire an ip via dhcp with dhclient -v eth0.1


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As it is said in Richard Hum's answer you can not configure one interface to be both AP and WiFi client. However I think that what you are trying to do is bridging between your ethernet interface and your wireless interface. For the question, yes, it is possible. In order to achieve that you need: Configure your wlan0 interface to run as a AP (explained ...


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adding -w to ping will allow the process to be much quicker. #!/bin/bash is_alive_ping() { ping -c 1 -w 1 $1 > /dev/null [ $? -eq 0 ] && echo $i ,Alive } for i in 192.168.213.{1..254} do is_alive_ping $i & done


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I know this was asked a year ago, but I've found a few solutions. The first one uses powernap and a script to check for specific running processes, and can be found here. Second I saw online was linux questions. This uses pings to another machine. I also flashed a router with DD-WRT to try out- at the dd-wrt wiki. These are very nice elegant solutions but ...


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I liked the answer from Mark Plotnick the best: Insert a system with two NICs that hides the router from the gatewayor or Install a virtual machine on the gateway that is attached to the eth0 and an internal interface with another subnet. Then route all traffic through the internal interface. Probably LXC should be most easy, though I never tried it out. ...


2

I have figured it out: iptables -t nat -A PREROUTING -d 3.3.3.3 -j DNAT --to-destination 2.2.2.2 iptables -t nat -A POSTROUTING -s 2.2.2.2 -j SNAT --to-source 3.3.3.3


3

The best solution would be to use two different subnets for your network, one for internal use and one for public/wan use, putting two interfaces in the same subnet will only cause you trouble. If you don't want to change the IP for the Windows DC, I suggest that you split the /24 to two /25, and use one for lower /25 for your internal net, and the upper ...


4

Google is using a lot of different servers and is doing load balancing between them using different DNS entries. If a single server dies another server will do its work. You can use the host command to look at your DNS configuration. My ISP currently resolves "www.google.com" as: $ host www.google.com www.google.com has address 173.194.32.240 ...


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I tried to comment on this but it says I do not have a high enough rep (50) to comment so I have to add as an answer. Sorry about that Just curious, can you mount it as root, then change ownership? Otherwise, I'm guessing it is something on the synology side. You will need to change ownership on the synology side and unfortunately I do not know this ...


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Ok, the problem was CentOS 7 blocking ports by default. I managed to connect to my server on port 2004 after executing the following command: firewall-cmd --zone=public --add-port=2004/tcp And this command opens the port when the VM reboots: firewall-cmd --zone=public --add-port=2004/tcp --permanent I found the information here.


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Some consumer-grade routers are confused by the bridged mode of VirtualBox, because then the host and the guest share the same MAC address. I suggest you add a second interface to your VM in host-only mode, for communcation with the host.


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Most likely if the server is available and you have an IP address for that server you should be able to ssh user@server-ip or ssh server-ip -l user but this will not work if you don't have sshd running on the server to accept ssh/secured tunneling. You need to enable sshd on your server by issuing: sudo /etc/init.d/sshd start You should also look ...


1

Something else must be up. The following test works fine for me. I'm using socat as both the client and server and I'm running tcpdump on my local system that I'm sitting at. 1. Setup socat server (listener) $ socat - TCP-LISTEN:2222,crlf 2. Setup socat client $ socat - TCP:192.168.1.80:2222 3. Now I run tcpdump: $ sudo tcpdump -Xi wlp1s0 src ...


1

I suggest you capture the packets and write them to a file with the <file>.pcap extension, and then open with wireshark. For example, in CentOS, to capture the packets: $ tcpdump -i eth0 -s 1500 -w /root/<filename.pcap>


1

This is an error in the networking code path and has no relation to hardware issue by itself. I doubt you have much of a concern there with regard to the device itself. You can check if you have network packet drops that may cause a problem using ethtool -S and on the other network devices just in case. It is possible that you have some network issue or ...


1

You cannot limit incoming traffic on the destination machine because it has already arrived. To properly do what you want to do, you need to put tc onto your gateway. This is probably not an option for you, but it's the way. Ingress traffic can only be policed, in that it discards packets that exceed the speed limit. This is inefficient because you now ...


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ping with a special interface: ping -I em1 8.8.8.8 OR ping -I br0 8.8.8.8


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The solution is easy. You did not take care of making tap0, a openvpn interface a part of br0 bridge. Detailed instructions you can find here. HTH, Cheers


5

When using Network Manager the default contents of the file /etc/network/interfaces is typically this: auto lo iface lo inet loopback NOTE: That is from my Ubuntu 14.04 system, but Debian should be identical to this. Where's it come from? If you search to find out what package /etc/network/interfaces is a part of you'll find that it's not. $ dpkg -S ...


0

If you wanna fix that, you need to remove the package biosdevname: sudo yum erase biosdevname


0

You could run your processes in multiple virtual machines. Then you could kill network access for some virtual machines but not others.


1

You can also use iptables to allow/restrict by udp/tcp ports on desired interfaces. For example let's introduce a rule in the filter table in the OUTPUT chain to allow all traffic on tcp/udp port 143 (IMAP). (sudo) iptables -A OUTPUT -o eth0 -p udp --destination-port 143 -j ACCEPT (sudo) iptables -A OUTPUT -o eth0 -p tcp --destination-port 143 -j ACCEPT ...


0

Try SystemTap. It should enable you to list all the process creating DNS sockets and dump the connection information to the console.


1

QEMU supports ICMP on the SLIRP backend. It is necessary to allow so called ping socket (PF_INET, SOCK_DGRAM, PROT_ICMP) for users in kernel. It is simple sysctl -w net.ipv4.ping_group_range='0 2147483647' See also http://lwn.net/Articles/422330/


2

Route Cache and Neighbor Tables are somewhat similar in that they both help decide where to send a packet next. The difference is the Neighbor Table caches entries at the layer 2 (ethernet) level; it helps translate IP addresses into MAC addresses. The ARP protocol is used to query for new entries to cache. A Route Cache works at layer 3 (IP). The ...


1

Verify that you have something similar to the following in /etc/network/interfaces auto eth0 iface eth0 inet dhcp eth0 could also be referred to as p5p1 or similar according to the modern naming convention. You can 'restart' all the network interfaces by bringing them down and up again with the following command: ifdown --all --no-loopback && ...


1

This comment by ott-- seems correct. If the screen dump above is complete, the service is only listening to 5500 on IPv6 and it's not listening to 1158 at all.


2

This fully valid and correctly. Also you can write names in one string with space delimiter: 127.0.1.1 debian mini mini.local The both variants is fully valid.


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can two hosts share the same IP Address without a conflict Short answer: No. Now as can be seen both mini and debian share the same IP Address. No, it's the other way round: Both names resolve to the same IP and that is OK. The IP 127.... are loopback Adresses, only available on your machine, read up here. Note that these IPs are not ...


0

The quality is dependent on the chipset of your device and its driver. Many will show a value of zero for quality while working fine. Even on those that do show a quality value, the algorithm for this value isn't standardised therefore you cannot compare between different chipsets. Even when using one adapter (as in your case) the fact that the ...


0

iptables - t nat -A PREROUTING -p tcp -m tcp --dport 3389 -j DNAT --to-destination 192.168.1.200:3389 iptables -A FORWARD -p tcp -m state -d 192.168.1.200 --dport 3389 --state NEW,ESTABLISHED,RELATED -j ACCEPT Suppose 192.168.1.200 is your windows.


1

From your comment (which would better be part of your question): I understand that TCP inherently has to retransmit packets, but I actually need to test out a functionality on my server, where I have to observe how the server behaves when it drops a TCP packet and it does not get retransmitted. So I cannot use UDP here. From my understanding you don't ...


1

Removing my comment and posting an answer instead. TCP was designed for reliability and error-checked transmissions. For this reason, it is in its very nature to resend packets which were not ACK-nowledged by the other end of the connection. If you don't want this mechanism to apply, you should probably just use another protocol such as UDP. However, if ...


0

Assuming you run cpanel on apache, first identify the access log file configured. This would be specified in the virtual host entry for cpanel (also known as a "vhost"). next, you can simply use this command tail -f /var/log/apache2/access_log # replace with the proper log file Tail shows the last few lines of the file, and -f tells it to wait & ...


1

Solution Description After many months of having this issue with intermittent WiFi connections and sometimes losing connectivity for hours at a time, Bug 1108801 on the Red Hat / Fedora bug tracker seemed to hold the solution for me. As described in Comment #12 on that bug, Realtek (the manufacturer of my wireless card) has updated drivers for my ...


1

The kernel doesn't read any configuration file. As a rule, kernels avoid accessing the filesystem; there are a few exceptions and variation, but mainly, the kernel launches a program at the location /sbin/init when it boots, and the only accesses filesystems on behalf of user land processes. Network configuration files (like other kinds of configuration ...


0

To find out which URLs are hit, consult the logfiles of your webserver. There's a multitude of awk scripts that can help you with finding which URLs are used by clients. Changing this won't affect CPU usage though. 100 client requests on /a/b/c likely take as much cycles as 100 requests to /d/e/f...


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There are a few dozen versions of netcat available, but this is likely because: You have 2 entries for localhost in /etc/hosts. One for IPv4, another for IPv6. The daemon is only listening on one protocol (likely IPv4). The client is first connecting via the protocol the daemon isn't listening on, and then trying the one that it is. For example: $ grep ...


2

This procedure is known as MAC Spoofing. Under GNU/Linux, the MAC address of a network interface card (NIC) can be changed by following the procedures below. Note: Before removing your GNU/linux MAC Address, you should take backup of the machine MAC Address. NOTE: MAC addresses used within this article are provided for example only. Substitute according ...


1

A bridge does not need an IP address to function. Without one it will just perform layer 2 switching, spanning tree protocol and filtering (if configured). An IP address is required if you want your bridge to take part in layer 3 routing of IP packets. As an example you can setup a bridge without an IP address in Debian/Ubuntu using the following in ...


2

When you are not sure of what something does, and the documentation doesn't say, you got to the sources, namely line 1588: if (matches(*argv, "change") == 0 || strcmp(*argv, "chg") == 0) return ipaddr_modify(RTM_NEWADDR, NLM_F_REPLACE, argc-1, argv+1); So, what it does? Returns the result of running the ipaddr_modify() function defined in line ...


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Is nameif deprecated? is it ok to continue to use nameif? Yes. Yes, it is. Just that there are more reliable methods to set the MAC of an interface, like using udev rules. If so is there an equivalent replacement? As mentioned before, you could use specials udev rules to set the MAC address however you like. In my case, the NIC's on my ...


0

2 years later I will throw this tidbit in, while wget and curl are not interactive, at least wget (and possibly curl but i do not know for sure) has the -c switch. So if you need to change your speed in the middle of a download and you presumably used the -c switch with the --limit-rate=x (which stands for continue from where I left off downloading earlier, ...


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It turned out that my DIR-850L was to blame, I have replaced it with a Asus RT-AC66R and everything is working correctly as expected now.


0

I see many connections like when I use netstat, are they all to the Internet? It depends on how you define “the Internet”. If you’re at home, and you have multiple computers, some of the connections might be to your other computers.  If you’re at work, it’s highly likely that you have connections to other machines at work. Are there network ...


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Q#1: I see many connections like when I use netstat, are they all to the internet? No not all connections listed in the output of netstat are to the internet. Many of these so-called connections are to files that are in use on your system. These are special files, one of which, is called a socket. A socket file allows an application to "talk" to ...



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