Tagged Questions

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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4 views

linux: how to troubleshoot forwarded port? [migrated]

My home internet connection has a static IP address (eg: 123.123.123.123) I have configured my router to forward port 9000 to an internal host (192.168.1.101). That host is running Ubuntu 14-04. ...
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2answers
38 views

Add a VLAN tag to specific UDP port traffic

I'm running an application in Ubuntu12.04 that I've written that does some remote switch management. I have only a single NIC connected to the network of managed switches, eth0 which is set with IPv4 ...
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0answers
8 views

OpenVPN Client recieves reply from Ping to Server but not from eth0 or non-server IP

I have been using OpenVPN succesfully with Layer2 bonding for over a year now. I have been experimenting with a more complicated setup on the local LAN using a ProxmoxVE hosting KVM VM as the server ...
0
votes
1answer
18 views

How to route an IP Whitelist to one VM and all other to a second VM on proxmox?

Is it possible on linux to have a whitelist of IP's that are allowed to reach a specific VM on the internal NAT? eg (public ip (proxmox) --> My VM for whitelisted IP's (192.168.0.1)), and if the ...
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0answers
3 views

Execute script on ipv6 prefix change [migrated]

How can I execute a script or program whenever my (world-routeable) IPv6 prefix changes? If there is (currently) no easy way to do this, a pointer to the corresponding Posix system calls would be ...
1
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1answer
22 views

Cannot Ping Devices Across Interfaces for Shorewall Single IP Three-interface Firewall on Debian Wheezy

Summary I am currently working on a three interface software firewall using Shorewall 4.5.5.3 on Debian Wheezy, and I'm having some difficulty with the loc (eth2) and dmz (eth1) interfaces. The fw ...
-1
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0answers
30 views

Send traffic out the right interface (Linux) [on hold]

I have two interfaces (wan and wan2). I want to use wan2 interface to connect to only one port (for example 9999). I do not want to use it to connect to other ports. Connections to the rest I want to ...
0
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1answer
29 views

why linux bridge shows 2 mac addresses for one qemu vm?

I am new to qemu networking and pretty confused about the following situation. I launched 5 VMs. Each connects to br0 through a tap device. I also have a dnsmasq listening on br0 for DHCP. The ...
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0answers
16 views

LXC container clone has no network and SSH stopped

I was having this networking problem with LXC containers (question and answer here:bridging LXC containers to host network with different IP range) and if I have found a solution, I still have not ...
0
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0answers
81 views

VMs on ESXi system, only able to use internal IPs

first off I am a bit of a network newb, I know the basics but that is about it. So I have a ESXi server running a few VMs. The set up is; -Master IP (controls the ESXi box) -Internet IP (for general ...
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0answers
5 views

Packet forwarding for guest VMs not working [migrated]

I'm am running some VMWare Fusion VMs on OS X, and I'm having trouble with networking. OS X has a Wifi interface with two IP addresses: en0: ...
-1
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0answers
17 views

How to setup public IP on localhost - Ubuntu [closed]

I have configured my Ubuntu server on localhost and got my router configured from my isp with IP. But I unsure how to configure it to make the server live. Can anyone please help me with ...
0
votes
1answer
14 views

How to change the ip range used for an IPCOP network interface

I am using IPCOP v2.1 I currently have a blue network with the range 192.168.0.0/23. I would like to change it to use 192.168.200.0/23. Is there a way to simply make the change, or am I required to ...
0
votes
1answer
27 views

Most outgoing connections blocked (kind of?)

I have a server which I upgraded from Ubuntu 12.04 to 14.04. Now I have some extremely strange behaviour (which I believe was not present immediately after the upgrade, but can't be sure): I can't (by ...
0
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0answers
5 views

How to Nslookup server IP and get actual VM IP not LB side virtual ip [closed]

I have a live application with a load balancer configured with a virtual ip on the lb side. When i try to nslookup the dns name , i always get the virtual ip (lb side). Is there any way i can get the ...
0
votes
1answer
26 views

rcp files from windows 2008 server to linux box? (Running rcp on linux)

I am trying to run rcp command on rhel6 server to copy over files from a windows 2008 server but see this error message. /usr/bin/rcp administrator@10.225.185.112:"C:\nfsqa-rhel62-vm01.root.keytab" ...
2
votes
0answers
29 views

How to route traffic through different interfaces based on the port number?

iptables -A PREROUTING -i usb0 -t mangle -p tcp --dport 8080 -j MARK --set-mark 1 iptables -L Chain INPUT (policy ACCEPT) target prot opt source destination Chain ...
0
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0answers
17 views

debian openssh-server resetting connection [closed]

I've installed openssh server on my debian wheezy machine. I was able to access it without any issues from my windows laptop using mobaxterm personal (which provides a very decent unix like ...
0
votes
2answers
87 views

OpenVPN Route Client Traffic Through VPN Server Tunnel

I have configured a vps following this tutorial, the server and client are successfully connected and can ping each other, server is at 10.8.0.1 and the connected client (android-OpenVPN Connect) get ...
0
votes
1answer
33 views

Temporarily block communication with host if its connecting to port X

I have a Linux VPS, and it's constantly being scanned, bruteforced by some rogue IPs. This VPS is my private server, that serves only to me, and I'm the only user of it. Also I am the only user who ...
0
votes
1answer
34 views

Linux router: User friendly, web-based traffic monitor app [closed]

This is not a tech question but I hope someone can help me out. I've been searching all over the web for an app like this, but I can't seem to find one: Friendly user interface where a non-technical ...
0
votes
2answers
36 views

How to forward traffic to different nics based on source?

I'm a newbie to IPtables, but am looking to do send traffic to a specific card based on the source. Here's what I would like: eth0 - all traffic comes in on this NIC Depending on the source IP, I ...
0
votes
0answers
9 views

allow double tagging on vlan interface

I have a single interface eth0 on my machine. I have a linux bridge to which If I add my interface I loose connectivity. So I create a vlan interface and add it to the bridge. All is fine now except ...
0
votes
1answer
23 views

ip route command with source option

I have multiple interfaces on my system catering to different subnets. I also have a pseudo interface which is a p-to-p driver for tunneling packets. I was trying to add routes using ip route command ...
0
votes
0answers
14 views

Linux: Reduce UDP Packets Error

I'm facing UDP packet receive errors (under Linux 'netstat -su' command). I have 10 x UDP processes running on Machine-A (RHEL 5.2) and each of them send 290-byte packet at 50 times per second to ...
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0answers
5 views

Why is ping resolving to an IP 198.105.254.228 for any random hostname that i type? [migrated]

I have a precise32 (ubuntu 12.04) vagrant vm running on my system. If i try to ping a random string, eg ping "thisip.doesnot" it resolves to an IP 198.105.254.228 . This is try for any other random ...
0
votes
1answer
34 views

Mount a SFTP remote filesystem that doesn't give shell access

I have a NAS that exposes its filesystem as SFTP, but it doesn't give any access to connect throught SSH as a normal user. I've tried to use sshfs to mount it from a remote webserver, but I receive ...
0
votes
1answer
33 views

How to achieve stateful fail over when using multiple uplinks?

I have multiple ISP lines over which I am load balancing the network traffic on my linux machine having multiple interfaces ( eth0, eth1 ,eth2, eth3) . This I am doing by creating the routing tables ...
2
votes
2answers
69 views

DNS points to the right IP, but I can't connect using DNS

UPDATE: This is now strictly a local problem, connecting remotely works (a dumb mistake I made.) I think it's now it's a loopback issue, which is a different issue, and likely answered in another ...
0
votes
0answers
15 views

Fail over in Lokiwall Firewall

I have configured lokiwall firewall on my linux machine having multiple interfaces. Dual Routing works fine. However, I wanted to know how does the fail over happen in case a link goes down. Do the ...
1
vote
0answers
29 views

Separate L2TP/IPsec VPNs with dynamic VLAN assignment

I am working on a Linux (Debian 7) VPN concentrator for different kinds of remote access. One of the offered protocols is L2TP/IPsec because of the client availability. I am using xl2tpd which in turn ...
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votes
0answers
21 views

Disable autoconfiguration of new network interface on Linux

I am running Ubuntu Linux and whenever I insert an external network card to my computer, it automatically creates a new interface (that is okay) but also instantly giving the interface an IP address. ...
1
vote
1answer
35 views

Debian port(s) not responding

I am fairly new to servers. I am trying to run a shoutcast server on debian. Shoutcast runs on a default port of 8000. My problem is it will not load when visiting xxx.xxx.xx.xxx:8000. When I log in ...
1
vote
1answer
31 views

iptables destination NAT from one range to another

I am trying to make destination NAT from one range (192.168.2.0/24) to corresponding ip addresses in another range (192.168.1.0/24). I have managed to do this ip by ip iptables -t nat -A PREROUTING ...
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votes
2answers
60 views

Telnet client on redhat linux

I am trying to install a telnet client in Red hat linux server which doesn't have internet connectivity. Red hat linux version less /etc/redhat-release Red Hat Enterprise Linux Server release 6.4 ...
1
vote
1answer
39 views

bacula backups very slow with TCP socket in 'unkn-4' state

Several bacula-fd clients are backing up to one bacula SD (using 2G disk files on massive RAID, not tape), usually 2-3 of them concurrently. It works fine, except when 2 bigger clients (about ...
0
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0answers
23 views

Why does ip_forward=1 cause inadvertant problems?

I did a google search and searched the Ubuntu forums, but couldn't find the answer I was looking for with my specific situation. What I have is the following: 2 handsets setup for VOIP ...
2
votes
1answer
84 views

Passing through RDMA network devices to docker containers

I'm wanting to passthrough infiniband to a docker container so that I can run some high performance apps over ipoib and use rdma. Currently, I'm doing this with xen virtual machines. Now I'm looking ...
0
votes
1answer
19 views

Forwarding traffic from one virtual interface to another

I have a router with two ethernet interfaces: eth0: 1.1.1.2 (with 1.1.1.1 gateway) eth1: 2.2.2.1 I created two new virtual interfaces: eth0:1 : 1.1.1.3 (with 1.1.1.1 gateway) eth1:1 : 2.2.3.1 ...
1
vote
0answers
34 views

Redirect Default Gateway Traffic in Linux to File

I am trying to troubleshoot one of my linux servers (ubuntu server). Therefore I want to intercept all traffic that is sent to the default gateway and then write it to a file: preferably some kind of ...
0
votes
1answer
35 views

how to run pptp over redsocks proxy

I have one (virtual) Linux box in Ubuntu, that has redsocks set up done. Inside the machine, I could confirm that the the redsocks did work (use wget to check the external IP). Now, I want other ...
0
votes
1answer
18 views

DNAT packet after decryption of ipsec

how to DNAT packet decrypted by ipsec. encrypted packet is: sourceIP: 192.168.4.6 destIP 10.10.0.100: If i simply : iptables -t nat -A PREROUTING d 10.10.0.100 -j DNAT --to-destination 10.0.0.5 ...
1
vote
0answers
51 views

Enabled Intel® I/O Acceleration but no bytes transffered

I enabled IOAT but it seems that no data is transferred using DMA for network: I enabled IOAT in bios. CPU is Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz. I loaded the module in ubuntu 14.04 ...
0
votes
0answers
31 views

CentOS 6.5 Bridged Networking Fails

I have a CentOS 6.5 Server that I wish to host VPS on, as well as installing SolusVM, to do this I need to bridge the network adapters for the Server and the VM's ( so the VM's can connect to the ...
0
votes
2answers
56 views

SSH tunnel (port forwarding) slow down a lot my mysql queries

I'm currently testing some configurations with vagrant (virtual box) to connect 2 servers (VM currently) together throw an SSH tunnel. The goal being to securely connect my web app to the database. ...
0
votes
0answers
43 views

How can I log and maybe even block IPs that send lots of incoming UDP traffic?

we run a voice / teamspeak server which receives legitmate traffic on port 9987 from many ips. Sometimes we get DDoSed. So people use single Servers and send 1-3 Gbits of UDP Floods to that port. This ...
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votes
1answer
47 views

How can I access a Virtual Machine on different subnet? [closed]

I have two virtual machine VMachineA and VMachineB using virtual box. VMachineA (CentOs 6.5) has two network interfaces: eth0 (IP: 192.168.3.48, GW: 192.168.3.1) and eth1 (IP: 10.10.200.1). ...
0
votes
1answer
66 views

Proxmox VE: Multiple shared public IPs with NAT configuration

I have a Proxmox VE (v3.3 @ Debian 7 Wheezy) and got 3 public IPs routed to that server. It is my aim to have multiple VMs sharing those IPs using a NAT configuration so that I can forward single ...
0
votes
2answers
137 views

Setting up a server with two NICs using two separate subnets (each on a different VLAN)

I'm using Ubuntu 14.04 (standard server install + OpenSSH, biosdevname=0 during instal to keep the network names simple) in an environment where I have two non-overlapping subnets M and N on different ...
0
votes
0answers
47 views

IPFire configuration as IDS behind router

I want to use an IPFire-Server primarily as an IDS behind an already existing router. The network's router (192.168.1.1) has access to the Internet and provides LAN-Slots for the clients. There is ...