Linux Networking refers to any networking function performed by a server running Linux. A Linux server operating as a router or firewall are the most common applications.

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Clients losing stateless ipv6 addresses

I'm having problems with Linux VM's at a certain VPS hoster. Periodically the hosts lose their ipv6 address. They go to 'deprecated' and then disappear completely. On the client side I have checked ...
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1answer
32 views

VPN Connection pooling?

I'm having a problem on PFSense https://forum.pfsense.org/index.php?topic=23914.0 where I can only connect one client with a PPTP VPN to a VPN Server outside out network. PFsense is our firewall and ...
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1answer
26 views

Windows network failing, not present on linux clients

got a really strange one for you all. I have a network setup using a linux machine as a gateway between various network segments (on seperate nic's) and virtual machines (one of which is a mail ...
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5answers
78 views

How do i down the server on the remote location for an hour

This is the doubt i have in my mind we can reboot the remote server using reboot command but how can we down the server for an hour or a specific time. In our case we login to the server through putty ...
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0answers
405 views

Open vSwitch double VLAN tagging is ignored

I'm trying to add a flow to a KVM machine using Open vSwitch 1.10.2 for it's networking, which double tag all traffic comming from one of the virtual machine's ports. I'm using the following command ...
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1answer
238 views

Ubuntu server - NIC suddenly loses connectivity

I'm scratching my head. I recently configured a server with two identical Intel NICs inside a DMZ. This morning at around 8:05, I successfully SSH'd in through the internal interface (via my LAN-based ...
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1answer
229 views

ssh connection freeze after password phase

I'm trying to connect to a server (Oracle Linux 6.3) and after I insert the password the session just freeze. I checked the audit log and I've authenticated successfully, after I restarted the ...
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2answers
134 views

Can I limit my autoSSH Tunneling Speed with trickle and ssh config file option?

When I use only ~$ autossh site1 it work perfectly, but whit trickle the pameter site1 is considered as DNS Name instead of conf block. User@VM:~$ sudo trickle -d 10 -u 10 -- autossh site1 [sudo] ...
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1answer
203 views

autostart ppp connection when vlan comes up

I want to start a ppp connection on my router on startup, but i need to have a vlan activated before. The problem is that if i ifup the vlan in the ppp interface, the vlan is not up when pppoe tries ...
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1answer
134 views

Designing a secure network layout

Over the last few years I've accumulated a lot of hardware that all currently exists on a flat network. There are a number of devices: my desktop, laptop, and computers of the rest of the people I ...
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4answers
233 views

Is there anyway to tell what user will receive data from inbound packet?

In linux, considering this use case: 1. User initiates http request for webpage to remote server 2. Remote server answers request and sends packets Is there any reference to the user who started ...
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1answer
209 views

storage traffic not going through Bonded interface

hi few days back i have asked a question here choosing network interface based on network purpose on my Centos server there are 4 NICs i bonded first two NICs and created bond0 with an MTU of 8600 ...
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1answer
228 views

squid3 with tcp_outgoing_address could not connect to anywhere

I have one server with 3 interfaces (3 physical lan card), which are connected to 3 different routers. Each router has a different subnet, i.e. the 3 interfaces of server belong to 3 different ...
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1answer
512 views

PPTP and windows 7 809 error [closed]

I want to connect from home to my router(linux mashine) at work. i have installed pptpd. i have added following fw rules: iptables -I INPUT -p tcp --dport -j ACCEPT iptables -I INPUT -p gre -j ...
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0answers
142 views

Linux routing: How to allow a device inside private network to connect a public IP over an unknown network?

Consider following network topology: ---------- ---- (my network) ---- | Device 1 | (.101) | 192.168.191.0/24 | ---------- | | ...
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1answer
1k views

Kali SYN Flood (Metasploit), not denying service

I have a server with apache2 installed. I tried to do a dos attack on the server by using kali linux syn flood attack, but i am still able to access the website on the server. msf auxiliary(synflood) ...
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2answers
357 views

Is it possible to do Linux network namespaces (netns) on MacOS?

Context - I'm trying to get a docker cluster running on MacOSX. Part of the install process for getting docker running is to install pipework. Pipework relies on /var/run/netns My question is: Is ...
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2answers
611 views

All traffic is passed through OpenVPN although not requested

I have a bash script on a Ubuntu box which searches for the fastest openvpn server, connects, and binds one program to the tun0 interface. Unfortunately, all traffic is being passed through the VPN. ...
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2answers
568 views

Force an LXC container to use its own IP address

Sorry if this question has already been asked. I could not find it, I have this setup : +---------------------------------------------------------------------------------------------+ |HOST ...
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0answers
28 views

Losing connection to server from several computers

I have a PostgreSQL server running Oracle Linux. In my network I have several workstations each running different OS (Fedora, Ubuntu, Windows). Every once in a while I lose connection from the several ...
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1answer
336 views

How to stabilish a VPN connection, only on port 8080

Infrastructure: Here's what I want, be able to connect to the website 10.10.100.32:8080 from my LAN on 'Router 1', and all the traffic outside the port 8080 should go to the default gateway 'Router ...
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0answers
279 views

php-fpm process in D state ,cause nfs wait rpc_wait_bit_killable

my wordpress site which is in clustered environment using NFS,nginx,php-fpm,mysql the infrastructure is hosted on amazon ec2.Under high load/traffic the php5-fpm process goes in D ...
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1answer
82 views

Trace route to specific page on a website [closed]

If I can access a site (ie: serverfault.com) through my proxy/firewall, it means that it will allow all it's subdirectories (serverfault.com//)? I can access the website site.com/ but it returns me ...
2
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1answer
333 views

Rate limiting udp packets destined to a linux machine

Is there any way to ratelimit udp packets destined to my linux machine? I am sensing some udp packet drops destined to my machine. Was there any default udp rate limiting conf in linux? I have seen ...
1
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1answer
56 views

How to set up custom multicast address

What would it take to setup a custom made multicast ip address in the network? Machines are linux. Let's say I want to have a multicast address with only some machines from the network as group ...
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2answers
2k views

Linux adds the wrong default route

For some reason my Centos 5.9 Linux 2.6.18 x86_64 wants me to have two default routes. Whenever I reboot the server, my routing table looks like this: [root@server1 ~]# route -n Kernel IP routing ...
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1answer
73 views

Network configuration for linux server

I had some troubles with a Linux server after being restarted. I can log to the machine but I cannot remotely access this machine via ssh client: ssh -v -v -v root@IP gives me connect to host IP port ...
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1answer
321 views

Can't reach multi-homed Ubuntu from different subnet

I have a multi-homed Ubuntu 12.04 server. I have two network interfaces connected to two different IP ranges. 2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen ...
2
votes
3answers
3k views

How can I achieve OpenVPN client routing without NAT on Linode

I've set up an OpenVPN network, and it is working properly in the sense that I can access the inner/LAN machines from the remote client. However, my problem is that all traffic from the remote ...
11
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3answers
17k views

What is the correct way to open a range of ports in iptables

I have come across articles advising for the following: iptables -A INPUT -p tcp 1000:2000 -j ACCEPT And others stating that the above will not work and iptables only supports multiple port ...
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0answers
273 views

Is there any way by which I can capture the wifi probe requests without using monitor mode?

For some reason, keeping the wifi interface in monitor mode on my machine is crashing it(its a raspberry pi, I'm assuming its crashing because of the amount of traffic being intercepted, but lets not ...
4
votes
1answer
214 views

Ban an IP when the server received an amount of data from it

What I need : There are many result for adding a drop rules by an amount of request per laps of time, but I need to drop by received byte count from a particular address over a period of time. ...
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3answers
434 views

In Linux, how can I automatically assign an IPv6 address to an interface based upon its IPv4 address at boot time?

On a CentOS 6 machine, I have a server with 2 NICs, eth0 and eth1. eth0 has address 192.168.0.1. I would like to create a script that parses the IP address of eth0 and assigns a similar-looking IPv6 ...
3
votes
1answer
566 views

Split tunneling through two VPNs simeltaneously

I want to run two OpenVPN client instances on an Ubuntu Server 14.04. I have both .conf files that can work independently (both are set to different interfaces - tun0 and tun1). I want to run both at ...
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1answer
226 views

How to exclude LAN traffic from IPSEC policy

I am trying to replace a Firewall/VPN appliance (Snapgear SG300) with another (Mikrotik RB951G-2HnD). My current router works, but, for the new mikrotik router, when I add the phase 2 tunnel, I can ...
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1answer
96 views

specific machines on subnet randomly lose connectivity, but the rest of the network is fine

Every physical machine is connected to a cisco switch and is on the same network 192.168.1.0/24 Every server I have is running Centos 6.5. A couple run KVM with a bunch of virtual machines. Most of ...
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3answers
227 views

Linux (Ubuntu 12.04) sending ARP requests over single interface

I have a system with custom hardware hooked up to 2 different ethernet ports on the same system. The interfaces are configured on the same subnet because the hardware (FPGA-based) has a hardcoded IP ...
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0answers
392 views

Shorewall redirect rule only working for some hosts in the same network

I'm trying to use Shorewall's REDIRECT action to intercept traffic destined for the firewall's port 514 (TCP and UDP) to port 5000 (also TCP and UDP), while also allowing direct traffic to the latter ...
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4answers
640 views

One second delay before tcpdump returns packets

Using Ubuntu, I'm trying to sync tcpdump sniffing with self-identifying "pings" from a client device. The problem is that getting precise starts and stops is made difficult by what looks like a ...
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1answer
654 views

Remote jmeter-server error while getting the results back after some time

I have a question, I'm using jmeter from my pc that drives a jmeter-server that is installed on a RHEL5.8 my version of java is : [jmeter@sem-osb logs]$ cat /etc/redhat-release Red Hat Enterprise ...
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0answers
93 views

muliple ssid's on same interface

I am working on centos6. I have 1 wifi interface. Can I create a virtual interface and create an adhoc network with it (my 'real' wifi interface is already connected to another ssid). This is what I ...
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1answer
838 views

Adding a whole IPv6 /64 block to an network interface on debian

I tried adding a whole IPv6 (/64) block to an interface using ip route add local 2001:41d0:2:ad64::/64 dev lo like described here on my Debian server, but I seem to be missing something. If I ping ...
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0answers
111 views

Can I route traffic destined for a local interface out another interface?

I'm trying to set up a testbench for a transparent device (called TD from now on). The goal is to make sure it forwards and logs correctly. I need to use just 1 machine + the TD in the test bench. ...
2
votes
1answer
114 views

iptables: does a scanner knows if you DROP packets?

I know how REJECT and DROP chain works. But, as I read here REJECT vs DROP when using iptables, user Dagelf said that the server still replies with TCP SYN/ACK. Does the scanner knows that a packet ...
2
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0answers
39 views

PIV authentication on redhat

I'm looking for a solution, or set of technologies, (etc) - for setting up a mixed (win 7, rhel 6.5) network with centralized login using smart cards (PIV). I know that this is possible using a ...
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0answers
204 views

Massively large number of packets dropped by interface

I have a virtual machine on ESXi 5 acting as a firewall for a PBX, it is running vyatta. When I run tcpdump on any interface, I get some ridiculous numbers! e.g. 4 packets captured 402 packets ...
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1answer
1k views

WMI: wmic linux agent query error: NTSTATUS: NT_STATUS_ACCESS_DENIED

Myself new to wmic and keep trying for a long time with default agent query approach. wmic is linux based WMI tool to talk to windows WMI agent. While trying to fetch data with wmic from nt(win7 with ...
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2answers
616 views

what does `pipe <number>` mean in `ping` output?

While running a test to diagnose some alleged network problem, I got this output from ping: --- r01c01b11n02 ping statistics --- 30000 packets transmitted, 29995 received, 0% packet loss, time 6309ms ...
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1answer
131 views

Software for emulating networks and NAT

I am working on a software that I need to test with different types of NAT, and I would like to set up a test environment I can reconfigure in different NAT modes. I would like to have: ...
2
votes
1answer
432 views

Assign different Hostname to different NIC

I have four network card on my server, I have assigned each with an specific IP now I want to set an different hostname for all the interface? What is the difference between setting the hostname in ...