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2

Some reasons I've found: 1. historical limitation: there is no MASK in the first implementation of tcpip, that means network nodes use the first number to distinguish network size and host ID. moreover, since class A is determined by its first octet, the higher-order bit is 0, so 127.x.x.x (01111111.x.x.x) is the latest segement of class A addresses. people ...


0

It seems that nmcli is unable connect to WPA2-enterprise networks. The networks have to either be manually configured or created via the various applets.


0

Some way to a workaround/solution for this problem is to use systemd-networkd. Set up a config file at /etc/systemd/network/net0dhcp.network (or similar) to: [Match] Name=net0 [Network] DHCP=true Rename net0 in the above to the appropriate network interface name. Now: systemctl disable dhcpcd systemctl enable systemd-networkd And reboot. (You can ...


1

For what it's worth, I needed to check the level of skew between two linux systems myself yesterday. Before going digging for tools, I used this unscientific method which gave me good enough results for my purposes (comparing timestamps of log outputs from the two systems). Launch a Putty session on each system and align them side-by-side Run the ...


1

are there any other typical webserver services that might break because of that? No. As long as you correctly configure rules for FTP (if you plan to use it) you'll be fine with allowing ESTABLISHED instead of ESTABLISHED and RELATED


0

Instead of setting a static IP like others suggested, I simply enabled "Bridged Adapter Mode" under "Network Connections", and then this made it such that each new virtual machine I made automatically had a new IP address. If you click "Bridged Adapter Mode" and it doesn't have any choices (i.e.the only option is "Not Selected"), then you can simply go to ...


0

Virtualbox is acting as a DHCP server for these virtual machines. You can either define static IP addresses for these machines, or simply set the IP address manually on each machine. If you don't know how to set a static IP address on your Linux system you need to learn how to do this, so I would suggest you go with the second option. There are detailed ...


0

I have used Virtual box also for testing. From windows 95 to 7 and Linux ;). I have used the NAT mode and then assign an static ip and always this has been working in any OS. This will work inside the same ip range from the LAN. Also please refer to this part of the documentation I guess this is a better way and the one required for yourself ...


0

You need to run netstat using sudo. The output indicates you're running a command such as netstat -tpn (though the exact arguments are unknown since you don't provide them). However without root privileges, netstat is unable to go poking around in the processes of other users (denoted by a - in the last column of your output), so the -p option will only ...


0

If I understand correctly what you are missing - From the question and comments, I understand you expect there is a PID and process name at the end of the line of netstat output? Like tcp 0 0 129.132.202.106:25 129.132.179.232:60154 ESTABLISHED 12775/nscd instead of tcp 0 0 129.132.202.106:25 129.132.179.232:60154 ESTABLISHED - Then, it seems ...


1

Shell syntax You seem to be confused regarding conditionals in shell scripts. Every shell command has an exit status, which is an integer between 0 and 255, with 0 meaning success and any other value meaning failure. Statements like if and while that expect boolean operands inspect the exit status of the command and treat 0 (success) as true and any other ...


0

Ping will return a 0 response if at least one attempt was successful. You might consider pinging the server you are connecting to until it is successful.


1

Just count the output of ip add show For example: root@xxxxxxlp01 ~ $ ip add sh dev eth3 | grep inet root@xxxxxxlp01 ~ $ ip add sh dev eth1 | grep inet root@xxxxxxlp01 ~ $ ip add sh dev eth0 | grep inet inet xxx.xxx.64.91/24 brd xxx.xxx.95.255 scope global eth0 inet6 fe80::224:e8ff:fe78:4dfb/64 scope link root@xxxxxxlp01 ~ $ ip add sh dev eth0 | ...


1

Netstat -an , netstat -rn, and lsof (before, and during the problem) may give clues. (Do they show too many open connections?). tcpdump may help too: start it just before establishing the connection and see what happens around the time connections start to die (and also a few minutes before the timeouts). And see if the NFS options are non default and ...


1

You indicate that your /etc/resolv.conf contains only nameserver 127.0.0.1. This means your DNS server is configured to be the local host and the local host isn't able to resolve host names. So it's one of two things: This is intentional. You have configured a DNS server on your local machine and its configuration is off somehow. You'll need to check the ...


0

It is a bug of Centos/RHEL 6.x minimal install. Network is not activated during installation, because for some reason, they expect all installations to use Network Manager. Change the line ONBOOT="no" to ONBOOT="yes" in the file /etc/sysconfig/network-scripts/ifcfg-eth0 (or whatever your eth connection number is). Btw, using ifconfig is deprecated, instead ...


0

Maybe your /etc/network/interfaces syntax is wrong. The parameter is vlan-raw-device(with minus) and not vlan_raw_device(with underscores); # INTERFACE LAN auto eth0 iface eth0 inet static pre-up modprobe 8021q pre-up ifconfig eth0 up post-down ifconfig eth0 down # Vlans auto vlan111 iface vlan111 inet static address 10.0.111.1 ...


1

First of all, is the host machine network interface is connected to the trunked port ? you can test this simple with the command vconfig to create the vlan interface on the fly, # vconfig add [interface-name] [vlan-id] # ( you will need 8021q module loaded ) # -e.g. vconfig add em1 100 ip addr show ... 12: em1.100@em1: ...


4

You can add the following line to /etc/dhcp/dhclient.conf: prepend domain-name-servers <working DNS IP(s) here>; This adds the DNS IP address(es) you specify before that/those provided by the DHCP. If you would like to add it/them after the address(es) provided by the DHCP, just use append domain-name-servers <working DNS IP(s) here>; If, ...


-1

You could do something like this: ${execi1 sshpass -p <yourpasssword> ssh dummy_user@server_name <monitoring_command>}


0

nmcli Wifi Get Wifi status nmcli radio wifi Turn wifi on or off nmcli radio wifi <on|off> List available access points(AP) to connect to nmcli device wifi list Refresh previous list nmcli device wifi rescan Create a new connection to an open AP nmcli device wifi connect <SSID|BSSID> Create a new connection to a password protected ...


1

Wayne's own answer is quite old by now. Arch has since switched to using systemd instead of init scripts. The Arch wiki's Avahi page has been updated and contains details on why the steps below are needed. In short: Avahi is a zeroconf tool, meaning itself needs no configuration to work once installed on all machines your LAN, but you must configure the rest ...


0

$iwconfig lists network devices. On the second line, it lists capabilities: $sudo iwconfig wlan0 unassociated Nickname:"<WIFI@REALTEK>" Mode:Auto Frequency=2.412 GHz Access Point: Not-Associated Sensitivity:0/0 Retry:off RTS thr:off Fragment thr:off Encryption key:off Power ...


0

The best bet I found was the "unit" option in the /etc/ppp/peers/... file. This option is an integer which names the interface pppX where X is the int after "unit". I ended up just naming the interfaces pppX in /etc/network/interfaces and using "unit" in the peers files to ensure they are named that way.


3

One of the things to look out for when cloning Linux systems is udev's persistent network device naming rules. udev may create and update the file /etc/udev/rules.d/70-persistent-net.rules to map MAC addresses to interface names. It does this with the script /lib/udev/write_net_rules. Each MAC address (with some exceptions; see ...


2

The syntax error is not related to the value you set to ServerRoot directive, your syntax for set ServerRoot is right. Run: httpd -t to check your configuration syntax. For you comment, simply putting this line in your /etc/httpd/conf/http.conf: ServerName localhost You can see more details in apache documentation.


2

Building on @mark-plotnick 's remark: The new hardware has a different mac address. The old mac address is still hard coded in /etc/udev/rules.d/70-persistent-net.rules. You could simply rename this file. In that case rebooting will recreate the file with the new mac address.


0

If you don't reset(modprobe or ethtool can help to reset the counter) the counter, the num you see from ifconfig will increase over time. So, generally speaking, the stats you get probably comes from your last reboot. The dropped section, usually indicates these meanings, you can check them one by one: If the traffic is high, say, for a 1Gigabit nic, ...


1

Run the software behind a reverse proxy. There are many to choose from. Probably the most popular is nginx, but many web servers have a way to configure them as a reverse proxy. There are also dedicated reverse proxy programs like Apache Traffic Server. Alternately, if you are running on Linux, you can do NAT port forwarding via iptables. This assumes you ...


0

you have to configure: sudo nano /etc/default/hostapd DAEMON_CONF="/etc/hostapd/hostapd.conf" Find the line above and tell the defaul config where your one is.


7

Your path looks ok, but does not include /sbin, which may be intended. You were probably looking for the command /sbin/ifconfig. If this file does not exist (try ls /sbin/ifconfig), the command may just be not installed. It is part of the package net-tools, which is not installed by default, because it's deprecated and superseeded by the command ip ...


0

The easiest way would be to take your WiFi config out of /etc/network/interfaces or similar and switch to Network Manager. Even if you set the connection to a system connection, it should be brought up in the background. This also gives you much easier WiFi connection management, at least for laptops that may be moving between networks. You could also take ...


0

Wireshark is a must try, as SHW suggested in his comment. It is a networking tool that shows any connections coming in or going out of your network. You can apply a filter to limit your search to your IP address range of your servers, and even track down what protocol is being used(so that you can figure out what is going on). It has a lot more tools that ...


1

Here is a sample code using @dkaragasidis suggestions. It reads the packet data, and passes it along. You can modify the packet in the handler function. Compile with: -lnetfilter_queue -lnfnetlink Add rule with (example): sudo iptables -A OUTPUT -p udp --dport 4444 -j NFQUEUE --queue-num 0 Remove rule with (example): sudo iptables -D OUTPUT -p udp --dport ...


3

Yes, the Netfilter framework of the Linux kernel is flexible enough to make this possible. I am not sure what are your expectations by saying "custom solution" and "if it can be done easier now". I assume you are prepared to write code in order to do low-level packet processing. The general idea is the following: Create iptables rules which will pass the ...


3

iptraf can show you a running tally per-socket so that will tell you which remote hosts are causing all the traffic. From the main menu go to IP Traffic Monitor and select the interface you want to monitor. Output is fairly intuitive:


1

I use a soft called IPTraf for quick monitoring of network connection. It runs on the terminal and can give you divers stats on the current connections status on the machine it's installed. you can also get a brake down based on the services used (or ports) which can be useful if your server only serves a particular function. Downside is that you need ...


0

You need a certain amount of data to make sure the database is accurate. So you can either manually take snapshots, or do real-time analysis. I have written a program which does a constant snapshot (every 15 seconds). It is rough, but it should help. Vnstatschedule


0

vnstat -u -i eth0 After installation you should run command above it will trigger database for this interface, vnstat -d For network statistic data breakdown by day, also with: vnstat -h for hours. vnstat should be runed in background by using crontab,for this you have to enable it, since after installation a cron job is created at /etc/cron.d ...


0

Try this, in your shell as root, # This will set the routing table to use the ppp0 interface for # 192.168.2.0/24 and 69.90.218.0/24 networks ip route add 192.168.2.0/24 dev ppp0 ip route add 69.90.218.0/24 dev ppp0 For every thing else (0.0.0.0) your default route should be your home GW # ip route default via 192.168.25.1 dev wlan0 proto static ...


1

So this issue is now followed here: https://github.com/yrutschle/sslh/issues/24 msw's answer might be exhaustive, but is also wrong: select() will block regardless of the socket's O_NONBLOCK status, that's basically what it's there for, and in fact code that uses blocking sockets when using select() is wrong. From Linux' select(2): "Under Linux, select() ...


0

On Unix: nc -l 192.168.1.10 32849 On Windows: telnet 192.168.1.10 32849 Where 32849 is an arbitrary port allowed in firewall rules, and the IP is the listening IP of the Unix machine. nc is the netcat utility.


2

According to netfilter documentation, redirection is a specialized case of destination NAT. REDIRECT is equivalent to doing DNAT to the incoming interface. Linux 2.4 NAT HOWTO -- Destination NAT So it means the first and second strings are equivalent. -A PREROUTING -i $INT -p $PROTO --dport $PORT -j REDIRECT --to-ports $NEWPORT -A PREROUTING -i $INT -p ...


0

from iptables man page: REDIRECT: It redirects the packet to the machine itself by changing the destination IP to the primary address of the incoming interface (locally-generated packets are mapped to the 127.0.0.1 address). DNAT: It specifies that the destination address of the packet should be modified (and all future packets in this connection will ...


0

There is an interesting tool which allows you to execute windows commands from Linux, the name is winexe. So you can send a message from the same machine to the console just typing: winexe -U domain/user%password --interactive=1 //WindowsMachine "msg console \"Your message goes here.\"" As you can see noleti's answer is much simpler but with winexe you can ...


1

How about NET SEND {name1 | * | /DOMAIN[:name] | /USERS} message on the windows machine, and echo "message" | smbclient -M name2 on the linux box? name1 and name2 are the netbios names of the machines.


2

First see if the interface got a IP address, using ip addr show or ifconfig # ip addr show ... 3: wlp3s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000 link/ether 00:24:d7:ae:dc:64 brd ff:ff:ff:ff:ff:ff inet 10.0.0.8/24 brd 10.0.0.255 scope global dynamic wlp3s0 valid_lft 3596sec preferred_lft ...


1

ntop I think the tool you're looking for is ntop. ntopng is the next generation version of the original ntop, a network traffic probe that shows the network usage, similar to what the popular top Unix command does. ntopng is based on libpcap and it has been written in a portable way in order to virtually run on every Unix platform, MacOSX and on Win32 ...


0

I had faced a similar problem when a working wifi connection stopped working after a dist-upgrade. (I have HP Pavilion g6, the driver being ralink3290). The problem was that the upgrade modified the module and so the driver that was being used was not the same as was supposed to be used by my system. Use this command to see which wireless controller ...


1

If you really want to set all the resources to a particular IP address, you can achieve it using tc command. But is it worth spending the time on it, it's upto you. :) From man page of tc command, Description Tc is used to configure Traffic Control in the Linux kernel. Traffic Control consists of the following: SHAPING When traffic is ...



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