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

learn more… | top users | synonyms (1)

5
votes
0answers
98 views

POST of MTU + ~798 bytes gets lost

I have a very weird issue with certain packets not arriving on the destination host. It happens when we transmit a POST that is somewhat larger than the MTU. We can reproduce it with this script: ...
3
votes
0answers
38 views
+50

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
votes
0answers
88 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 ...
3
votes
0answers
434 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 ...
3
votes
0answers
114 views

VMXNET3 nic loses the ability to update ARP table after N hours

I have a fedora 18 VM that stops updating the arp table on eth1 after running for a number of hours to days. There are other VMs on the same hypervisor that can access all of the same networks without ...
3
votes
0answers
237 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 ...
3
votes
0answers
77 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
votes
0answers
480 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
votes
0answers
192 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
votes
0answers
181 views

Overlapping subnets - VPN

I have Site to Site VPN on Debian box which is setup by rackoon. It works fine, however because subnetworks overlap NAT is used on both ends of the VPN (1.1.1.1/32 & 2.2.2.2/32) On both subnets I ...
3
votes
0answers
1k 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
votes
0answers
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 ...
2
votes
0answers
28 views

SSH tunneling is faster than OpenVPN, could it be?

Logically, VPN should be faster than SSH for tunneling, because: It's running on UDP and not TCP (so no TCP over TCP) It has compression However, today I tested Redis replication over both ...
2
votes
0answers
20 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
votes
0answers
22 views

Http Request Hangs Client Side

We've run a website for several years with thousands of visitors. Very rarely the following problem happens to a certain group of users: A certain user of that group makes a client side action on his ...
2
votes
0answers
30 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 ...
2
votes
0answers
45 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 ...
2
votes
0answers
39 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
votes
0answers
48 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
votes
0answers
191 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
votes
0answers
95 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 ...
2
votes
0answers
121 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, ...
2
votes
0answers
112 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
153 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
121 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
votes
0answers
2k views

eth0 NIC Link is Down repeating message in kernel log

I've noticed since few days ago that same repeating kind of messages occurs and I positively can say that nothing was intentionally changed (installed/uninstalled) in that period. here's sample of ...
2
votes
0answers
361 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
votes
0answers
38 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
votes
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
votes
0answers
111 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
111 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
249 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
votes
0answers
368 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
1k 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
345 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 ...
2
votes
0answers
702 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
140 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
votes
0answers
193 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
votes
0answers
158 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
232 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
290 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 ...
2
votes
0answers
199 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 ...
2
votes
0answers
1k views

OpenVPN resets connection repeadly

I have a OpenVPN server installed in an Amazon instance with Windows Server 2008 R2, and there's my client. First i connect to my VPN For some reason when i try to connect to my VPN server and RDP to ...
2
votes
0answers
774 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 ...
2
votes
0answers
140 views

Openstack with no fixed range

I test-drove various Openstack installations (devstack, offical guides and so on) on VM's and me&my devs love it, so we acquired the HW to set a small production cluster (3 IBM x3650, 4 ethernets ...
2
votes
0answers
1k views

Issue with Netgear GS108T Managed Switch and Jumbo Frames

I recently purchased a Netgear GS108T managed switch and I am trying to configure jumbo packets between my NAS (Thecus N4100Pro), PC and managed switch. I should mention the fact that I was able to ...
2
votes
0answers
157 views

How do I make dnsmasq serve IP addresses via IPoIB?

I have a cluster farm that I'm setting up. The nodes (computers in the farm) are connected via ethernet & IP over Infiniband. I'm needing to netboot the nodes and thought dnsmasq would fit well ...
2
votes
0answers
530 views

Troubleshooting Redmine performance

I've got a Redmine instance (Bitnami Stack) that's unusually slow. Because I'm just trying to get to the bottom of this, I have some theories which I'd like to discuss here. So, if anybody has any ...
2
votes
0answers
498 views

Clickonce applications being allowed through firewall

The company I work for uses an application that is deployed through clickonce. This means that everytime they update said program the program regenerates in a new location ie: ...