Networking refers to the technologies and techniques that enable the interconnection of devices and applications allowing them to communicate electronically.

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918 views

Creating Virtual Network Azure - The Gateway was not created

It's been sitting at "THE GATEWAY WAS NOT CREATED." for hours after creating a Virtual Network in Azure. Is this normal? What should I do? We previously created a network in the wrong DC, it didn't ...
4
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74 views

Cisco DNS doctoring or Hairpinning?

I've the following configuration: CISCO 881, IOS 15.2(4)M6. On WAN interface is configured the 86.34.156.48/29 subnet from our ISP. Behind the router is staying 2 webserver. NAT: 86.34.156.51 <> ...
4
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96 views

Configure Juniper M320 as Ethernet/STM transparent converter

There is Juniper M320. We need to move ALL the traffic from one port to another. Everything that comes to one port goes to another and vice versa. No snooping or any other processing is required. One ...
3
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36 views

Why would you internally use NAT?

I work at a fairly huge company as a software engineer and I would like to understand why an enterprise would internally use NAT. We have several data centers, somewhat geographically close to each ...
3
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39 views

Procurve script/automation

This may be a stupid question, but I'm normally not a network admin, but circumstances have me there. I'm trying to disable down ports on a switch, but have a boatload of them, I'd like to configure ...
3
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43 views

IPSec bandwidth between two Pfsense hosts has predictable, variable bandwidth

I have a IPSec tunnel between two Pfsense machines. Both machines are connected to a 100mbps symmetrical connection. The latency between the two routers is ~70ms. I'm using AES-GCM-128 and SHA1, both ...
3
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0answers
262 views

TCP connection stuck in SYN_RECV state despite ACK received

My client and server are both internal machines. tcpdump on both client and server show all three parts of handshake are communicated, however netstat on server shows SYN_RECV, and on client shows ...
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288 views

Automating Configuration of VMware's vSwitch (OpenStack/libvirt/Nova)

There's a lot of talk now about VMware integrating with OpenStack now. I've noticed that Nova network service is working with VMware's standard and vDS. Deploying a full OpenStack instance is not ...
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87 views

Configuring Container with bridges and vlans (server only?)

I have two groups of lxc contianers on a server and want to isolate their network traffic for security reasons. I will be using port forwarding so the containers much each have separate IP's. I know I ...
3
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546 views

Limiting bandwidth with hashlimit (e.g. kb/s — not connections!) doesn't work, though the man page says it should

According to the iptables-extensions man page hashlimit can do bandwidth limiting: "flows exceeding 512kbyte/s" => --hashlimit-mode srcip,dstip,srcport,dstport --hashlimit-above 512kb/s ...
3
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233 views

snmp MIB-TCP::tcp not showing any usage

I am trying to configure MRTG on all of my servers for making a network weathermap, this requires running SNMP which MRTG gets the information from. So, I installed it on two servers the exact same ...
3
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226 views

High %soft CPU usage during high network load on ixgbe

We have an Intel 82598EB 10GBE NIC. The network load is composed of lot of small sized UDP packets. To simulate a DDoS, from another server we pushed ~100k pps small UDP packet (just some Mbit of ...
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2k views

NAT64 configuration with tayga on Debian 6

I'm trying to implement NAT64 with tayga on my server and came to a point where I'm not sure how to proceed. My server is connected via one IPv4 address and one /64 IPv6 address block to the ...
3
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0answers
940 views

Enabling IPv6 with OpenVZ using Proxmox 2.2

I'm trying to enable IPv6 on my Debian nodes (OpenVZ) using venet; my host is under Proxmox 2.2 (kernel 2.6.32-16-pve), and it seems the routing fails. My host correctly pings all my nodes; all my ...
3
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1k views

Jenkins slave fails handshaking on windows

I have a win2k8 machine used as our CI master server (Jenkins) I have various other servers running as slaves The master is listening for slave connections on port 2000 SlaveA - can connect to ...
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0answers
13 views

How do I enforce preferential routes with BGP & Quagga?

I have two routers that I'm setting up currently and they will be feeding my network of servers with a private AS number provided by the datacentre. What I want to do is provide both a VRRP failover ...
2
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61 views

Debian does not shut down interface with ip link set … down

I have a really specific question for a trunk-testing environment. I have this network setup: +------------+ +------------+ | | +-----+ | | | eth0 ...
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85 views

Server 2008 R2 NIC in “Unidentified Network” state after connectivity loss is restored

I am having trouble with 2 servers, both with the same symptoms. When they are reconnected to the switch after losing connectivity, they stay in an "unidentified network" state. Only after cycling the ...
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96 views

Intermittent Connection Issues on High Traffic Servers

Some brief background: We've been getting reports of very intermittent connection issues from our users. Several times per day, users will have to reload the page they're on due to a connection ...
2
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166 views

Cisco 3850 flooding all ports because CAM table not populated?

Encountering a strange issue with a Cisco 3850 that is in use as a core switch. It is flooding all ports on the switch with traffic. After investigating more, it appears that the CAM table is not ...
2
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31 views

Certificate can only be used by network service account

Issues : Our service is using one certification for partner service call. It worked well in IIS site which is running as network service account. But when we run test the code as administrator ...
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114 views

Display port security state of an HP 3COM 5120 switch port

I'm using an HP-A5120-24G-SI switch and I'm asking how to obtain the current state of the port-security module for a certain port. I'm able to view the current settings using display port-security ...
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35 views

Device not accepting connections from a forwarded port. Security Issue?

I am forwarding a port through to a PLC/Management unit type device for a heatpump. The device accepts local connections from the LAN on port 80. It runs a normal web site on port 80 for management. ...
2
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141 views

Debugging slow Quickbooks in multi-user mode

Building 1: Main QB server with 15 users Building 2: 12 users accessing the QB server There is no sluggishness in building 1. Building 2 has issues. They can RDP to the server fine with no lag but ...
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34 views

IGMP Snooping limitations and when do you start to use PIM?

At a head end I've just inherited, all our multicast streams run on cisco switches with IGMP snooping enabled. Because all these streams are to be kept local and isolated we've never really looked ...
2
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0answers
129 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 ...
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46 views

Which openstack instance has a certain IP address

There are IPs on my network that are not configured as fixed or floating in Neutron, they are simply claimed by an instance (e.g. via ifconfig eth0:1 ip.add.re.ss). How do I get openstack (possibly ...
2
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0answers
65 views

Non-local IP for next hop in routing

I'm working with an MPLS network and I am slightly confused about some route entries. Interfaces are (these are fake IPs): eth0 10.10.10.1/24 (LAN) eth1 10.9.9.1/24 (MPLS) eht2 2.2.2.2/24 ...
2
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424 views

Network Layer 7 Deep Packet Inspection linux solution that isn't a all-in-one distro?

Overview: I have software that has our Edge/DNS servers hardcoded into them, DNS queries returned from DNS servers are not being masked properly. I need the DNS entries that are returned from BIND ...
2
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0answers
136 views

Apache Instance in Private Subnet not returning packets

How can we get the Apache instance in a private subnet to work? Configuration Public subnet with 1 NAT instance Private subnet with 1 App instance Details 1. Masquerading is turned on NAT on via ...
2
votes
0answers
161 views

How to setup multiple OpenVPN connections on a server for a single localhost app to use on CentOS 6.5?

I have a scenario where I need to run several OpenVPN connections at one time and to allow a singular application to access each of these connections. How wold I go about starting up several ...
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0answers
169 views

Debian, IPv6 is not asssigned to interface

I have a Debian 7 Server with several networks and KVM VMs running configured: 2a01:4f8:191:439b::/64 144.72.132.208/29 The IPv6 Subnet is splitted into /96 Networks to assign each bridge a own ...
2
votes
0answers
2k views

Ubuntu 12.04/14.04 - apt-get 404 Not Found [IP: local-dns-server-ip 80] through proxy

I am trying to setup an ubuntu server (12.04 or 14.04) and have installed the server image onto the system I am using. Everything works fine until I try to run sudo apt-get update. When this runs, I ...
2
votes
0answers
251 views

How to reset Winsock without reboot

I often need to execute a Winsock reset, running netsh int ip reset and each time I have to restart the system. Is there a way to avoid that? Should I kill and restart explorer.exe? Restart some ...
2
votes
0answers
143 views

Debian server - DNS stopped working after static IP reassignment

Due to changes in the LAN router, I had to modify the static IP of one of our servers. It still succeeds in finding the external world (ping google.com), but only temporarily - when I access one of ...
2
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0answers
457 views

squid transparent proxy https

i hope someone can help me. i have this problem: squid is running as a ssl transparent proxy, and at the moment it's receiving all the traffic with these two iptables rules: iptables -t nat -A ...
2
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0answers
41 views

List subfolders somewhere in the path with rsync

I'm developing a program, that will recursively "walk" through Linux repositories, look for PXE-related files and create gPXE configs. I met across a problem with the structure of Ubuntu catalogs on ...
2
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0answers
40 views

Strange faulty 16000d response timing in gdevtools for specific XHR

We have some XHR on our website, that is reported in Google developer tools' network timeline as Receiving for 16035.5 days. There actually is a response, and for sure it does not take as long as ...
2
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0answers
126 views

xenserver vm routing fails half the time on the same network

I recently switched from openstack (due to complexity) to xenserver at work, I ran into an issue that I can't solve, I can ping the server all the time but the vms part of the time. here is a ...
2
votes
0answers
160 views

I am not able to connect to my server from my leased line internet connection

I am having some troubles connecting to my Fedora server from my static IP ISP connection. Usually I can ping that server with no problems. But other times it just gives me timeout responses. When ...
2
votes
0answers
287 views

How to make Statsd talk to Ganglia on EC2 (localhost)

As per topic, Im just trying to make this simple setup work. The services are running fine, but as far as I can tell statsd doesn't send anything over to ganglia. Ganglia is working fine I guess since ...
2
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0answers
419 views

How to preseed options before network in Debian/Ubuntu PXE installation?

I'm trying to fully automate an Ubuntu installation over the network, but the preseed file is loaded only after the network adapter detection. Even with those options in the preseed file the ...
2
votes
0answers
2k views

ActiveMQ - “Cannot send, channel has already failed” every 2 seconds?

ActiveMQ 5.7.0 CentOS release 6.3 java version "1.6.0_26" Application server: Tomcat In the activemq.log, I'm seeing this exception every 2 seconds: 2013-11-05 13:00:52,374 | DEBUG | Transport ...
2
votes
0answers
498 views

Should I set rto_min for a route inside data center?

We have a few dedicated server rented in a data center with debian 7, kernel 3.2. We use one of those servers as a database server. The network between our application server and database server is ...
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990 views

Wireless router country codes: what issues can these actually cause?

Running the network diagnostics tool on my Mac, I get a messaging about "Conflicting Country Codes" stating that: "A nearby wireless router has been detected which is identifying itself as ...
2
votes
0answers
173 views

Solaris 10 invalid ARP requests from 0.0.0.0? Link up/down every hour or 2

The guys at the data center where I'm hosting a server running Solaris 10 are telling me that my server is making a lot of invalid arp requests. This is an example of a portion of what was sent to me ...
2
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0answers
233 views

Ping request fails first request on one subnet/NIC. Other traffic very slow

I have a server with 2 NICs each configured on a separate subnet: NIC1 xxx.xx.151.10, mask 255.255.252.0, gateway xxx.xx.148.1 NIC2 xxx.xx.148.10, mask 255.255.255.0, gateway None, but I tried ...
2
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0answers
205 views

Martian Source & Servers losing network

First off, I am pretty new at diagnosing network issues through linux. I have an intermittent problem with our LAN servers. They seem to lose all connection to the network and if I disable the adapter ...
2
votes
0answers
291 views

Drop Events on a Dell Powerswitch 2724

I have a rather simple network setup here at an office. We utilize a Sonicwall TZ205N, plugged into a Business-Class Cable modem for internet, and plugged into three Dell PowerConnect 2724 gigabit ...
2
votes
0answers
353 views

Configuring LACP across a IBM B50G switch stack

Is it possible to configure LACP (Link aggregation control protocol) that spans across two IBM B50G stacked switches. Below is an illustration of what I am trying to accomplish. I have currently ...