Networking refers to the technologies and techniques that enable the interconnection of devices and applications allowing them to communicate electronically.
12
votes
9answers
36k views
Any way to find unused IP addresses on my network?
How can I locate unused IP addresses on my network? The DHCP server keeps assigning the same address and I need a different IP address to test my application with. The software would need to run on ...
0
votes
1answer
29 views
Split management network from data in Xen Server
I'm working on configuring our existing pool of four hypervisors running XenServer 6.1 to use a separate management network.
Currently the setup is a single link with a public address over which all ...
2
votes
2answers
56 views
Can I use IPs assigned to virtual network interfaces in a bash script?
I'm wondering if it's possible to dynamically read in the IP addresses of network interfaces for use in a bash script. Something like:
#!/bin/bash
MYPUBLICIP= get_eth0_address
MYPRIVATEIP= ...
3
votes
0answers
84 views
Packets not entering FORWARD chain
first of all, this is not an every-day routing issue. The setup is fairly complex, so let me state it before.
I got a router with, lets keep it simple, 3 interfaces. eth0, eth1, eth2.
eth2 is used ...
1
vote
1answer
38 views
How to setup completely wireless network to retrieve data
I have a situation and I'm not sure the best way (or at least the terminology) to find a solution. There are four rooms that CANNOT have any cabling run into them from the outside. There are 4 ...
1
vote
0answers
16 views
Changing the mac address in a libvirt xml config file breaks network connectivity for the guest
I'm using Xen with libvirt and trying to set it up on a bridged interface. I am able to install an OS and everything works as I would expect. If I save the xml output from "virsh dumpxml guest", edit ...
4
votes
2answers
3k views
File encryption solution for network share
We have recently received a few client contracts where all client files must be encrypted at all times. The challenge we are having is sharing encrypted files and simultaneous access on network ...
1
vote
0answers
26 views
Network traffic is not being forwarded from a VM to the network using a bridged interface with Xen + libvirt
I'm having trouble getting network access from a VM that I'm running using Xen and libvirt. I've been trying different things and reading similar posts online for a couple of days but I'm really stuck ...
4
votes
1answer
96 views
Linux networking port exhaustion
I've done as much research as I could on this without digging right off in the kernel source. There seems to be a large amount of disinformation/incorrect info on the subject, so I hope this answers ...
0
votes
1answer
28 views
How do jabber servers find each other and how do they proof the authority for the domain they handle?
Recently google chatback has been turned off, and I was searching for an alternative that allows visitors of my website to isntantly message me, without the need of having a login at facebook or ...
1
vote
2answers
3k views
Domain connection shows as “unauthenticated”
I have seen various different questions for this problem floating around but either the circumstances arent the same or the solution doesnt work so thought i would post it to see if anybody has any ...
0
votes
0answers
47 views
Connecting to Mac on iPad via local network
For my business, I have a product that is built with a Mac Mini running things at the core. On this Mac Mini, I have installed Apache and PHP to serve dynamic web pages locally. Users access these ...
-1
votes
0answers
20 views
Sever networking stops after few hours but works after suspend/wakeup [migrated]
I have an Ubuntu 12.10 Desktop PC acting as my headless home server. I can ping it and access the files and folders on the computer with no issues. But after a few hours of running, its networking ...
-5
votes
0answers
40 views
Why is my local ip address not starting with 192.168…? [closed]
I am connected with my university network and we have ip addresses starting with 10.10.... My question is, since our college network is a local area network, why dont we have ip addresses starting ...
0
votes
1answer
609 views
Ping server NETBIOS name returns wrong IP and “Destination host unreachable”
Problem server is Windows 2008 R2 VM running on VMWare ESXi 4 host. Single network adapter manually assigned single IP address (192.168.1.11).
When I ping the server from any other network computer, ...
0
votes
1answer
40 views
how to check which CPU cores are serving rx queues for a particular NIC and if RPS is enabled
On my host (RHEL 6.3, 2.6.x kernel) , eth2 generates irq # 60-65. I validated it via /proc/interrupts.
The /proc/irq/61-65/smp_affinity shows following bitsets for 5 queues
1000
0040
0400
0100
0010
...
2
votes
1answer
64 views
Linux machine does not answer an ARP request
We have this situation: A router, which is an Ubuntu VM, has multiple VLAN interfaces on the same physical NIC. Those VLAN interfaces are dynamically configured and torn down and attached to networks ...
1
vote
1answer
17 views
If I have a process which is supposed to be receiving data from multicast, how can I check if it actually is?
I can check gstack, but just because I see the listener threads on the recv call does not mean that call is not returning. One other thing I thought was to do something like:
netstat -lupe | grep ...
1
vote
1answer
796 views
Why won't vyatta allow SMTP through my firewall?
I am setting up a vyatta router on VMware ESXi,
But I see to have hit a major snag, I could not get my firewall and NAT to work correctly.
I am not sure what was wrong with NAT but it "seems" to be ...
0
votes
0answers
33 views
“Destination port unreachable” when pinging computer in another subnet [migrated]
In my home network, I connect to the Internet through a router (192.168.1.1). I also have another router (192.168.1.15, 192.168.2.1), this one using OpenWRT, configured as a wireless client. One of my ...
1
vote
2answers
67 views
Disable IP on bridge
OK, I'm running libvirt on my server, I've only one interface, in order to use public IP in my VM I need to setup a bridge, everything OK so far.. But I don't want to setup a IP address at bridge ...
0
votes
1answer
57 views
What would my over subscription be for my network?
I have 24 racks with 20 servers each connecting to 2 by 48 x 10G switches in each rack (NIC teaming). The switchs then connects to another 2 by 48 x 10G switches in 2 aggregation racks.
What would ...
0
votes
4answers
134 views
Is asymmetric latency common in practice?
This is a follow-on to a question posted on stack overflow about whether it is possible to determine the one-way latency of a point to point connection without using externally synchronized clocks - ...
0
votes
1answer
44 views
Is it worth to set up a different network interface for connections to MySQL?
I have a high load website served by two servers: web server with nginx and php, and database server with mysql. Web server serves all the static content and connects to MySQL and outside world ...
1
vote
2answers
101 views
Route data to internet through a specified interface
I have a main server (Centos 6.2) which serves as router/firewall and has virtual machines.
Virtual machines are in the network 10.0.0.0/8 and everyone else (there is DHCP server) is at ...
5
votes
5answers
713 views
NAT as a firewall
Network Address Translation ( NAT ), seems to sort of act as a firewall for the hosts behind it because they are not available. Although I would never rely on this as my firewall, what are its ...
-2
votes
1answer
61 views
Can ISP Throttle Wireless but Not Ethernet? [closed]
Is it possible for my ISP to throttle only wireless connections but NOT wired (ethernet) connections?
Seems impossible to me, but I think it is actually occurring. Here is my scenario:
I have a ...
4
votes
1answer
396 views
TCP Windows Size vs Socket Buffer Size on Windows
I am new to Windows networking. When people talk about TCP tuning on Windows platform, they always mention about TCP Window Size. I am wondering whether Windows uses the concept of "Socket Buffer ...
1
vote
0answers
19 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 ...
0
votes
1answer
42 views
Is there a command to check the network bandwidth of a server? (linux)
I am trying to compare different cloud server providers and one thing I am interested is the network bandwidth like 1Gb/s. Many vendors are not explicit in this respect.
Is there a way in Centos to ...
1
vote
1answer
34 views
Network issues regarding p4300 SAN - cannot manage p4300 through CMC
I am having an issue with my p4300 LeftHand SAN. It is a 2 node iSCSI system. Each one has 2 nics which are teamed into a cisco switch. The VMware cluster is connected into this switch as well with ...
1
vote
1answer
1k views
NIC models for HVM guests in Xen 4.0
Is there a list of NIC models that I should use with various HVM guests in Xen 4.0? Is there even a list of possible choices for the model=field? I'm planning on running both Windows and FreeBSD ...
0
votes
0answers
49 views
2013 - Lost connection to MySQL server at 'reading initial communication package', system error: 0
I know you can find tons upon tons of threads and information about this issue, but non of the threads I've found provided a useful answer. (In my case) I've tried to fix this issue for about 12 hours ...
6
votes
1answer
213 views
DNS issues on Google compute engine
I'm experiencing some interesting network issues, which I can reproduce and work around, although not explain - therefore I ask you! :)
I have a setup with two servers, both located in Google's ...
0
votes
1answer
67 views
Source policy routing breaks layer 2 domain routing
I have a Linux (Ubuntu 12.04) machine (c220-1) that has multiple interfaces. The two of interest here are:
eth2: 10.10.0.131/24
eth3: 10.20.0.2/24
The default route is set to 10.20.0.2. However, ...
0
votes
3answers
793 views
Dual-homed server DNS registration issue
In our environment, most Windows Servers are dual-homed.
The first NIC, called 'Public' is the one:
used by the servers to communicate with Active Directory
with a default gateway set
via which the ...
0
votes
6answers
1k views
'Slow down' A DHCP server on purpose
As the title implies, May look like a silly question, But what i'm trying to do,
Is to have 2 DHCP servers in one network.
One only leases IPs to Bootp clients (And if the client re-requests ...
0
votes
1answer
20 views
Could not connect to bridget WM with Win2012 host
I have the following setup.
A physical PC with Windows Server 2012 (host OS) with VMware workstation 9.02 with:
Windows Server 2012 (guest OS)
Ubuntu 12.04 (guest OS)
The guest OS's both run as ...
0
votes
1answer
2k views
let Opera Mini (in Microemulator, on OS X) hit local network
I just set up Microemulator on OS X (Leopard) and am running Opera Mini 4.2, hoping to test a mobile website I'm developing.
Opera Mini can hit public websites, but it can't to hit my test sites on ...
1
vote
3answers
67 views
Measuring network latency
I want to measure performance of the network, especially latency. We are performing stress tests of a system that sends live audio / video data over the network. When there are multiple simultaneous ...
4
votes
1answer
40 views
STP in a mixed environment
Good day all,
We have some a mixed environment of Dell Powerconnect and Cisco switches. On both brands of switches, I am seeing numerous STP topology changes. I've decided to try on work on the Dell ...
2
votes
3answers
2k views
Change gateway on windows 7 from command line
I am trying to find how to change the default gateway on a Windows 7 machine from the DOS prompt.
Thanks!
0
votes
2answers
175 views
24 Port Switch versus 4 x 8 Port Switch
While prices for switches in the end-customer sector are decreasing, I found that 24 port switches are much more expensive than multiple 8 port switches with the same speed.
Are there any ...
0
votes
2answers
702 views
How to route broadcast packets from machine with two network interfaces on same subnet
I run RHEL 5 and have two NICs on one machine connected to the same subnet:
eth0 192.168.100.10
eth1 192.168.100.11
My application needs to receive and transmit UDP packets (both unicast ...
1
vote
2answers
59 views
No IP address on Windows SBS 2008
We have a strange problem in our Windows SBS 2008 and it just came over a night.
The problem is that Windows says that we are not connected to any IP4 or IP6 network but it recognises that the network ...
-1
votes
0answers
18 views
Indicate that a segment I have authority to use “inverse resolution”. (Berkeley Internet Name Domain) [closed]
I have Centos installed on my virtual machine.
I show some settings that I have:
In /etc/sysconfig/network:
NETWORKING=yes
HOSTNAME=dns1.example.com
In vi /etc/hosts:
192.168.1.3 ...
0
votes
0answers
39 views
Need to programmatically cycle openvpn
I'm running openvpn client 2.2.0 on ubuntu 11.10 and I need a way to programmatically restart the process. I have a script that starts up openvpn fine the first time, but then on subsequent restarts ...
-4
votes
0answers
44 views
How do we create a network of 100 Computers in one building from scratch? [closed]
One building, divided in 3 stories. I want to create a network of 100 computers in this one building.
How many Routers, Switches and Hubs do I need? How many Straight and cross over cables do I need? ...
0
votes
0answers
35 views
How to configure 100+ ipv6 on vps? [duplicate]
I have vps with Ubuntu 12.10 x32 and several ipv6 onboard
root@ :~# cat /etc/network/interfaces
auto eth0
iface eth0 inet static
address 38.--.--.--
gateway 38.--.--.-
netmask ...
2
votes
5answers
1k views
Open ports broken from internal network
Quick summary: Forwarded port works from the outside world, but from the internal network using the external IP the connection is refused.
This is a simplified situation to make the explanation ...
