1
vote
0answers
40 views

VM with 2 network cards

I have a VM with 2 network interfaces which is running CentOS. One connects to a private network (192.168.6.x) and another to our company wide network. When I try to ssh the private address from a ...
0
votes
0answers
6 views

squid3 wccp2 setting up gre tunnel from squid proxy to router

I am trying to setup a gre tunnel between a squid 3.1 proxy on linux debian, and a cisco router. I want to have web requests to port 80 to pass through the proxy first. I have created a gre tunnel ...
-1
votes
1answer
42 views

Routing traffic through different interfaces based on incoming IP

I am trying to setup a unique setup where I have to route traffic that's incoming to one server and have the traffic based on the incoming IP address get routed through to different interfaces and ...
-1
votes
1answer
35 views

private network with single IP multiple servers

I am trying to set up a subnet in our company. We got several (10+) Linux servers for computing but we can only get 1 static IP (company policy, 10.x.x.x address). So the idea is to place a routing ...
0
votes
0answers
5 views

Sporadic packet loss through RT-N65U router with cable Internet [migrated]

My setup looks like this: TM902S (EuroDOCSIS 3.0 cable modem) <-> RT-N65U router <-> several computers in LAN The router is running this firmware with a custom traffic shaping script. The ...
0
votes
0answers
22 views

Is there a software that can show me network requests in detail by scripts and application? [closed]

I write web application, small java and .net applications that talks to each other over network or internet. Is there any software for Mac, windows and linux that can show me log or network requests ...
1
vote
1answer
17 views

ifcfg-eth0.200 is not responding to arp broadcasts

I have a Centos router doing a stupendous job in a setup similar to this: eth0 --> no IP eth0.200 --> 192.168.200.1 eth0.201 --> 192.168.201.1 ... so on up to eth0.213 --> 192.168.213.1 I have ...
-2
votes
2answers
65 views

Linux: How to find out which ports did my application use [without being root]? [on hold]

I have the following question. On a CentOS machine I run an application which connects to another system. I am interested in finding out on which ports (input/output) the communication happened. The ...
4
votes
1answer
79 views

Massive packet duplication

Short Version: We've had a problem with a particular server receiving massive duplicates of packets. After much fault finding we found the problem was caused by a switch sending my packet out every ...
1
vote
2answers
285 views

Low latency TCP settings on Ubuntu

There is a server for measurements running on Ubuntu in my lab . And there is C program, which receives data through TCP connection and should as soon as possible send a reply. Network latency when ...
0
votes
3answers
54 views

is it possible in this case to get two IPv6 networks to communicate over the IPv4 Internet?

I have a setup of a laptop connected to a cellular IPv4 network (3G usb dongle) and PC connected to another IPv4/IPv6 network. Both have been configured to run as IPv6 routers and each has its IPv6 ...
1
vote
1answer
23 views

Is there a way to get current txqueue utilization on e.g. eth0 or tun device?

I have detected drops on my tun0 interface. They seem to have been caused by low txqueuelen setting. Now as I increased the txqueuelen value for the network device and there are no more drops yet - ...
2
votes
1answer
74 views

What is the correct iptables rule when NATing multiple private subnets?

I have a Centos minimal 6.5 acting as a router. eth0 is connected to a Cisco switch trunk port, allowing VLANs 200-213. I have several VLAN interfaces just as this link suggests: ...
-1
votes
1answer
38 views

tc-qfq is classless error

I'm using Linux 3.0.101 with iproute2-3.4.0 on a router and I'm getting this error: tc qdisc add dev eth2.2 root handle 1: qfq --> OK tc class add dev eth2.2 parent 1: classid 1:10 qfq weight 1 ...
0
votes
0answers
27 views

network inbound from other subnets refused to server A, Server A can go outbound to internal networks, but not internet

I have a RHEL 6 server with 4 NICs on 192.168.2.[30-33]/24 Set with DHCP reservations via infoblox, I have checked and the MACs all match up. ifconfig shows /24 for every netmask, and the routing ...
0
votes
2answers
21 views

IPFIX collector with extension support

I need a tool to collect IPFIX records and log the contents of each packet to a log file or database to validate the accuracy of an IPFIX emitter. This IPFIX emitter sends enterprise extensions in the ...
0
votes
1answer
56 views

Linux Unraid route traffic through different interfaces

I have two interfaces: eth0 and tun5. eth0 is an ethernet to a router and tun5 is a VPN tunnel. These are on an UnRaid server, which is based on Linux. It's a headless server so I access it via SSH. ...
-2
votes
1answer
31 views

Users unable to connect due to an unknown plausible reason [closed]

========================= Warning: Long thread; includes a lot of information to give you some basic understanding of my issues. If you rather not read it, then here are my questions: 1) Does Linux ...
0
votes
1answer
51 views

Linux: Duplicate network interface to simulate link failures

I run Ubuntu. I need to add some latency and/or some network errors to see if my application can handle with network failure ( connecting & disconnecting ). I found "tc" tool which will be helpful ...
0
votes
1answer
33 views

incorrent subnet/mask combination

For a network interface, I have defined a range of addresses for DHCP. 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 08:00:27:5a:3e:be ...
1
vote
2answers
33 views

Counting number of connections in a pcap file

What tool can I used to get a count of the number of TCP and UDP connections inside of a pcap file?
0
votes
0answers
39 views

Ubuntu refuses to route packets for public subnet through linknet

I've run into the novel concept of routing through a linknet from my new ISP, and am currently trying to get a /28 routed properly on my Ubuntu 13.10 server. However, this is proving futile. This is ...
0
votes
1answer
34 views

How can I bridge a VM to a remote network?

I have a system running QEMU/KVM (via libvirt). One of its VMs needs to have a presence on a subnet that is not local to the VM host. I have a Linux system on the remote subnet. Is there a way to ...
1
vote
1answer
38 views

Directed ARP requests do not arrive at bridge interface

I'm baffled by the following weird bridge/arp behavior under Linux. It somehow seems to filter directed ARP requests, whereas it should forward them to the other end of the bridge. To test, I run the ...
-2
votes
2answers
29 views

What is the difference between search domains and nameservers? [closed]

I've usually seen two kinds of entries in /etc/resolv.conf on certain servers. The domain-name-servers entry specifies which DNS to use for resolving hostnames to IP addresses. Recently I saw an entry ...
0
votes
2answers
38 views

UDP Packet drop? [closed]

Multicast packet got drop between the server, multicast work on udp which unreliable so drop packet is expected Question: is their a way or utility available to capture udp packet at os kernel ...
1
vote
2answers
57 views

simple setting for traffic shaping

I have: 2 linux boxes (A, B) 1 switch (S) 1 gateway (G) [I have no control over this one] +---------------+ | switch S +-------+ +---+--------+--+ | | | ...
0
votes
1answer
37 views

Iptables -j REJECT unavailable [duplicate]

I am somewhat new to Linux networking and running in to a issue with iptables I am just not making any headway on. Two notes before I get in too it. iptables is version 1.4.14, and it is a custom ...
3
votes
1answer
78 views

Device eth0 does not seem to be present on new kernel with virtualization modules loaded/compiled on kernel 3.15.6

cat /etc/udev/rules.d/70-persistent-net.rules SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:15:5D:02:14:22", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0" ...
0
votes
1answer
49 views

Avahi How do I setup multiple servers that originally have the same hostname

Let me explain what I'm trying to do: I'm creating a Linux Distro Image that will be installed on a SD Card Setting the default hostname to myHostname.local This is all on my local network This is ...
0
votes
0answers
17 views

Making proxies on Debian

Hi guys I am trying to create SOCKS Proxies on my VPS and currently am not getting too far so any help is well appreciated. Here's a few details on my VPS: It is running Debian linux, has 512mb ram ...
1
vote
1answer
83 views

Hyper-v Virtual Network Switch Configuration

I have Hyper-v Running. What I am trying to do is setup a CentOS firewall box which will forward all traffic to the 2nd VM CentOS box which has an internal adapter and only seen by the 1st VM ...
0
votes
2answers
68 views

Connect two servers with RJ-45 cable and iptables (without switch!)

I have two servers and server_1 is connected to INTERNET port (of server farm) at eth0. No switch. They connected with cable from (server_1)eth1 -> (server_2)eth0 : ifconfig of (server_1): eth0 ...
1
vote
1answer
70 views

TLS Error on OpenVPN

Client: OpenVPN 2.3.4 64bit (Works fine connecting to my pfSense at home) Server: OpenVPN 2.2.2 installed via yum Followed this guide: ...
0
votes
1answer
63 views

How to set DNS exclusively for a Network Namespace in Linux

I've created a network namespace in Linux. I thought there was a resolv.conf file for each namespaces created but it's not the case on my system. I don't have the following path ...
4
votes
4answers
233 views

How do I Control the Ordering of Network Interfaces?

I'm attempting to configure a machine with 3 NICs, the first two are built-in GbE controllers, the third is a 10GbE controller. Via NetworkManager, I've configured the 'first' GbE NIC (which at the ...
1
vote
0answers
123 views

Haproxy using 10GB Memory and 100% CPU with 50k connections

On a Ubuntu 14.04 x64 server, Haproxy uses 3.3 GB of memory and 6.8 GB of swap, while handling 52k connections. The CPU usage also keeps spiking to 100% before most of the traffic was redirected to ...
0
votes
1answer
48 views

Configuring a linux machine for high inbound network load

I'm running Ubuntu 12.04 on an a dual processor Intel E5-2620-HexCore, 64GB of RAM, 1Gb network link. When downloading a single test file from a location in the same datacenter (Public network) I get ...
1
vote
0answers
42 views

ping: sendmsg: Operation not permitted (sometimes)

On a Ubuntu 14.04 running Haproxy, after a service haproxy reload, Haproxy is suddenly reporting all servers behind it as down. After some digging around, I noticed that ping is not working properly, ...
0
votes
1answer
17 views

VLAN inside Guest machine/domU

hi is it possible to create VLAN inside guest machines? using Xen 4.2 with Ubuntu as dom0,all guests are Centos On host i have 2 bridges in two different VLAN connected to bridge, virtual machine ...
0
votes
1answer
66 views

Multi-homed network?

I have a network with a layout like this: ******* ****** ******* ****** * SW1 * --------- * R1 * ---------- * SW2 * ---------- * R2 * ******* ****** ...
4
votes
4answers
224 views

Centos server keeps jumping to address instead of static assigned address

I have a headless Centos server that I've configured with a static IP address. I've disabled Network Manager, avahi-daemon etc. Whenever I restart the network it just jumps to 10.155.90.100 instead of ...
4
votes
2answers
171 views

TCP connection through IPSec (Linux/Strongswan) stalls after exceeding PMTU

The backups (via Bacula) of one of my servers (“A”) connected via IPSec (Strongswan on Debian testing) to a storage daemon (“B”) don't finish 95% of the times they run. What apparently happens, is: ...
-1
votes
1answer
69 views

How should I properly block outgoing http traffic with iptables

I'm experimenting with iptables, and I'm trying to allow all outgoing requests for HTTPS, but to block HTTP. I have the code below; Chain INPUT (policy ACCEPT) target prot opt source ...
0
votes
0answers
39 views

OpenVPN in bridged mode, confusion about interfaces

I'm trying to understand some fundamental OpenVPN/networking basics. Let's assume the following scenario: there is an openVPN server which is already configured properly it runs in bridged mode the ...
4
votes
1answer
175 views

Making TCP dump without packets loss

How to make a TCP dump where it is guaranteed that all the packets that really pass through the network are captured, and nothing is missed? Details: We have an issue with 3rd party vendor who ...
0
votes
2answers
80 views

How to use the new ifdown and ifup?

I would like to change the MAC address on a Fedora 2o webserver, but it seams that ifdown and ifup doesn't work like they used too before systemd were introduced. This is what I would like to do ...
0
votes
1answer
36 views

Using OpenVPN and iptables in combination

Let's imagine there are three networks, WAN, LAN-A and LAN-B. In between, there is a firewall server connecting the networks to each other. iptables ensures the following things: There is no way for ...
4
votes
4answers
191 views

Monitor an internet link to a remote host

I have a Debian Wheezy server running Xivo (let's call it A), this server has 2 interfaces: eth0 and eth1 . There is no default gateway and only a few servers are statically reached from A. eth0 has ...
0
votes
1answer
89 views

Is it possible to make the server accessible from two internet connections

how to make this: have: Centos 6.5 WAN1 eth0 44.44.44.44 (DEFROUTE=yes) WAN2 ppp0 95.95.95.95 (DEFROUTE=no) HTTP server work and available only in eth0 DNS server work but port 53 blocked in ...