Managing and using network connectivity on a unix system

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Using OpenConnect for a VPN, Linux Mint 17

I'm trying to setup a VPN connection. My corporate IT team went and hid under a table when I said Linux so you guys are my last hope. I'm trying to port all my the settings from my Windows 7 machine ...
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20 views

SNAT with firewall-cmd?

I have an interface with multiple IP Addresses (on CentOS 7), which is in zone "external" (with masquerade on). I want to specify that, if a connectiona attempt to a specific address goes out, to use ...
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2answers
47 views

Browsers doesn't see an aliases in /etc/hosts

A firm where I'm working uses an internal site with documentation and etc. where all references made e.g. to «srv-moss» — this names should be defined in hosts file, where I did added it. It works ...
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46 views

How to mitigate error “kernel: nf_conntrack: table full, dropping packet”

We recently had a problem with one of our servers (Debian Squeeze) becoming unresponsive during heavy-ish load. Looking at the kernel logs, I think this is the cause: kernel: nf_conntrack: table ...
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54 views

how to enable wireless connection in linux mint 17

I have Dell Inspiron 2200 with "Broadcom 4318" The wifi worked fine with "Linux Lite". It still works with the ethernet connection. But NO wifi! The "Driver Manager" shows blank ("NO proprietary ...
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38 views

How to forward Remote-Desktop Port across interfaces using ufw?

Machine A has two network interfaces: Network eth0: 10.10.20.0/24 Network wlan0: 192.168.1.145/24 Machine A has 192.168.1.145 as Default Gateway, and also a route to pass 172.16.0.0/16 to ...
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37 views

PPPoE Connection using WiFi Connection in Linux

I found that a majority of possible solutions contained two common threads. I attempted both: Using the pppoeconf command, and doing other steps , I was able to connect and surf the net. Great! I ...
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13 views

How to set proxy with a config file provided in freebsd

I'm currently trying to update and install packages and other things on a FreeBSD server, but I’m blocked by my proxy. I'm in an university, and there are a few proxies before to go on the internet. ...
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2answers
74 views

ping: unknown host with iptables enabled

I can't ping www.google.com. However I can ping the IP address: ping 74.125.237.142 At first, I thought it is a problem with my DNS settings. But I checked my resolv.conf, hosts, and hostname ...
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2answers
54 views

no internet connection for a kvm guest. what could be wrong?

I have setup a kvm win7 guest on a debian host. It's been up and running for a while now, but I had not done much with it. What I had done (for sure) was to download putty. Today I wanted to try and ...
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1answer
31 views

Binding to not existing interface

I've just noticed the very weird situation I don't have a good explanation for. The machine (debian) has one interface with one IP address assigned: # ifconfig vmbr0 |grep inet inet ...
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14 views

SoftEther Logging

I've installed SoftEther on Centos 6.5 and can't seem to get users to connect. Anyone know if there is a way to increase the verbosity of the logging? Regards
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25 views

Set up a VPN network between servers

I'm looking to set up a VPN network between a few servers. However, my needs are a bit unconventional - I need to have the VPN clients grouped into 2 groups: masters, and clients. (Both master and ...
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3answers
44 views

How to get the original MAC address of a network card, after the OS modified it?

How can I find out the original MAC address for a network card, after it was modified by the OS? dmesg doesn't provide it, and the logs in /var/log too, and dmidecode doesn't provide it too and ...
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1answer
70 views

Rsync connection reset by peer

rsync --protocol=29 -rav -e ssh --include '*/' --include='*_en*.xml.gz' --exclude='*' user@server:/path/ Content is downloading from remote server but after while I get this error: Write failed: ...
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1answer
68 views

How to force network to wait for DHCP with systemd-networkd?

I'm using systemd-networkd to configure my interfaces: [Match] Name=enp3s0 [Network] DHCP=v4 It works quite well except that at boot, some services are not waiting for DHCP to finish. For ...
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2answers
39 views

Wifi and ethernet unstable (takes many tries to connect, disconnects)

Both my WiFi connection and my Ethernet connection have recently (I'd say about a week ago) become unstable, without any change in the configs. Now in order to connect I've to try several times and ...
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21 views

Are there any loopholes in IP restricting sshd?

Say that i want to only allow username/password logins on my private network, but restrict all external sources on to key/cert login. I would do something like this: RSAAuthentication yes ...
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3answers
1k views

Why are TCP/IP sockets considered “open files”?

I need some assistance grasping what I'm sure is a fundamental concept in Linux: the limit for open files. Specifically, I'm confused on why open sockets can count towards the total number of "open ...
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27 views

Send/Receive bandwidth monitor per application?

I'm looking for a tool that can monitor my system and create some summary how many data was sent or received by each application/process. Is something like this? I found nethogs but he shows only real ...
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43 views

Networking issue in IBM x3650 after install Ubuntu 14.04.1

I have a problem making TCP connections after a fresh Ubuntu 14.04 installation. First of all, after booting the interface is always off. In my case the interface is manually configured and named em2. ...
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1answer
30 views

What's the difference between TYPE and DEVICETYPE directives in ifcfg scripts?

While learning the Network Teaming objective of the RHCE (RHEL7) exam I noticed that examples use DEVICETYPE directive in the ifcfg scripts for master and port interfaces. I knew there was TYPE ...
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19 views

iptables forward too many interface

Can I build a FORWARD rule which gives both an in/out and SRC/DST IP host? I need to create a rule that does the following: PC -> switch (non-mgmt) -> Linux Router (VLAN) -> world: block ICMP $ ...
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1answer
31 views

Establish connection between Qemu Raspbian machine and Host

Objective: I would like to install several virtual (emulated) Raspberry machines on the laptop, connect them to each other and to the laptop. Afterwards I would like to send tcp packets from virtual ...
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1answer
25 views

KVM bridge network requirement

I am following the following guide on installing my first KVM HV. http://wiki.centos.org/HowTos/KVM I thing I do not understand is the bit about bridge network setup. It states its optional, but what ...
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94 views

Sending SMS trough a modem attached to another server using ser2net and socat

I don't know exactly how to troubleshoot the issue I'm having, so I'll ask here. I have a USB 3G modem attached to a physical machine (server4) (running ProxMox (Debian Wheezy)), and I can send SMS ...
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1answer
27 views

Create FQDN in LAN for Windows systems without samba

I just set up my raspberry pi. It is working great and I can easily access it from my local Windows machine using SSH. I gave it a custom hostname. I can acces the pi with this hostname only when the ...
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1answer
50 views

linux namespace, How to connect internet in network namespace?

I want to test linux network namespace. The current problem is I cannot connect internet in the namespace here is my commands: 1 Create network namespace netns1, create a pair of veths (A and B) ...
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1answer
57 views

How to set static IPv6 IP address to embedded Linux board using ifconfig (busybox)?

We want to set static IPv6 IP to custom embedded Linux board. So far we could enable IPv6 in Linux kernel and Busybox. We could test that kernel is IPv6 ready. We tried to configure a static IP using ...
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32 views

How do I write the rule that has an edge server forward a clients request to an internal network server and back?

I have a network situation as follows: -server1:1.1.1.1 -server2:2.2.2.2 -tunnel 10.8.0.0/24 -client: 3.3.3.3 I'm trying to have client IP 3.3.3.3 do an HTTP request from the 1.1.1.1 server. ...
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24 views

Testing DHCP range; multiple addresses per interface

I set up a DHCP server; I have a range defined, for ~1k hosts. Is there a way to test all the addresses? This is the first time I have a task like this and I would like to know what will happen when ...
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1answer
38 views

iptables routing incoming IP to another destination IP question

I have a test setup: server1:1.1.1.1 server2:2.2.2.2 client: 3.3.3.3 I'm trying to have client IP 3.3.3.3 do a HTTP request from the 1.1.1.1 server. However I want the 1.1.1.1 server to pass this ...
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12 views

My kdeinit4 process hogs all wifi traffic

It seems my kdeinit4 process eats up a good part of my wifi bandwidth by sending a lot of stuff. #netstat -tap Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address ...
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2answers
36 views

Gateway with colliding networks

I have an Ubuntu-box as a gateway with two interfaces. The first one (eth0) is the internal network and has the following address: eth0: 192.168.1.1/24 The second one is connected to a router from ...
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0answers
43 views

Configure a usb wireless adapter when hotplugged

I have a pc connected to the internet on eth0 and I have a usb wifi dongle: I succeeded to configure it as a hotspot to which I can connect from my mobile devices so that I can share the pc internet ...
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1answer
62 views

Why can I ping google.com but not www.google.com [closed]

I can $ping google.com and get data back PING google.com (74.125.227.96): 56 data bytes 64 bytes from 74.125.227.96: icmp_seq=0 ttl=56 time=26.939 ms 64 bytes from 74.125.227.96: icmp_seq=1 ttl=56 ...
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22 views

Plain Bridge vs. Open vSwitch

Is there any performance benefit in using Open vSwitch over a plain bridge?
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3answers
69 views

Server running on guest Linux VM will not accept connections from Windows host

I have a simple echo server program running on CentOS 7. If I run both the client and the server in the VM, I can connect to the server. I'm using VirtualBox with the "bridged" network configuration. ...
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2answers
52 views

tcpdump doesn't appear to be capturing any data, why?

I'm trying to capture data with tcpdump like so: $ sudo tcpdump -Xi eth0 I have the device and the PC connected to each other. On both sides I launch a simple test application that sends a message ...
0
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1answer
59 views

NAS set-up issue with NFS protocol in linux Mint

I have a Synology NAS that I'm trying to map in my Linux machine as if its like a regular HDD drive. I have looked all over the internet without being able to figure out how this thing works. I have ...
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0answers
54 views

Debian WLAN to LAN bridge, double IP address

Target device is Raspberry Pi, with Debian running kernel 3.12.9-1+rpi1. I want to bridge USB WLAN card with local Ethernet NIC, but I want to have 2 IP addresses on that bridge interface, one from ...
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2answers
92 views

Can neither PING LAN nor when it is connected to OpenVPN

I try to configure OpenVPN on my raspberry-pi (minimal raspbian-wheezy distro). I run OpenVPN behind a Router and want to connect from a Windows client. I can connect to the server but I want to ...
2
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1answer
104 views

Default contents of /etc/network/interfaces on Crunchbang/Debian?

I've broken localhost on my computer. For example python -m SimpleHTTPServer and curl http://localhost:8000 don't work. The contents of my /etc/network/interfaces is empty. Does anyone know what the ...
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20 views

Intel Centrino Wirelsess-N 1030 not getting connected on generic mode in ubuntu 14.04

I upgraded Ubuntu from 12.04 to 14.04. After upgrading neither WLAN and ethernet work and also does not work in recovery mode (enable networking) or root shell. When booting the previous version ...
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20 views

Are layer 2 protocols part of NIC or NIC's device driver at kernel?

Are layer 2 protocols like IEEE 802.2 (LLC), PPP, HDLC, frame relay, etc part of NIC or NIC's device driver at kernel? When we configure layer 2 protocol to be used like PPP, where is the ...
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2answers
62 views

How can I deny internet access to all processes except the chosen ones?

Sometimes I am forced to use really narrow Internet bandwidth of 56kbps. On my Ubuntu desktop I have too many programs, that frequently check something on the net - and hunting and disabling them ...
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1answer
35 views

Find service by network activity

I see a strange DNS request at tcpdump and I want to find service which is originated from. I've already tried to find it with different monitoring tools but still no luck. Is there any proven ...
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1answer
38 views

Difference between route cache and neighbor table

Our Ubuntu server runs as a router for thousands of devices. With the growing number of connecting clients we have noticed 3 overflow problems in the kernel log: 1. Route cache chain too long 2. ...
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2answers
60 views

Can two hosts have the same IP address in /etc/hosts?

can two hosts share the same IP Address without a conflict. This is how my /etc/hosts looks like :- $ cat /etc/hosts 127.0.0.1 localhost 127.0.1.1 debian 127.0.1.1 mini Now as can be seen ...
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55 views

CentOS 7 gnome Version Network issue

I just installed Cent-OS 7 with GUI Interface, but now I am logging in but I can not connect to network, in virtual machine I see it's connect with bridge (VMware) but I cannot connect to network, I ...