I have a larger network about 1000 pcs on LAN
I need to know that what is the fastest way to discover nodes/ pc on lan for admin pruposes
Abdul Khaliq
You could try sending out a ping message but it's unlikely that all nodes will reply to it.
The most reliable way to detect nodes is to perform ARP requests. You'll need to control a node inside the LAN (ARP requests don't pass through routers).
Related
i have a measurement setup where i want to trigger an oscilloscope base on a network package arriving. I have good results for a few seconds but somewhere between 20s and 40s i get a wrong trigger. My research showed that this could come from the arp packages send from the device. I tried to disable the arp sending but then the whole network went down. Now i'm trying to find a solution where i change the rate at which the arp packets are send without success. So i'm asking you if you know a way to either disable or send as few arp request as possible.
For your information i'm working on a Linux machine. Any help would be appreciated.
I allready tried:
#ip link set arp off dev eth0 <--- results in network down
changing the values for:
/proc/sys/net/ipv4/neigh/default/gc_interval
/proc/sys/net/ipv4/neigh/default/gc_stale_time
/proc/sys/net/ipv4/route/gc_interval
/proc/sys/net/ipv4/route/gc_timeout
with no success
Thx draufunddran
TL;DR: Disabling ARP on your machine will eventually cause other nodes on the network to stop sending packets to your machine (that is why your network appears to go down).
If you want to completely disable ARP packets on your network, you will need to manually program ARP tables on other nodes on your LAN (subnet) so that they know how to map your host's IP to a MAC address to send to on the LAN. This is a difficult thing to do if even possible since some nodes on your network may not offer the ability to program their ARP tables manually.
Ok. I am creating a teamviewer like app. And p2p connection is the best route based on my research on p2p. I want to know weather teamviewer works fully on p2p, and is it possible to create such an app without using any dedicated server and a static public ip address. I mean i do know all nodes in a p2p n/w act equal, but then how will these maintain a connection having dynamic ip addresses. Hoping someone can explain how p2p establishes this.
They do not need a static IP. But in absence of a static IP you need some discovery / address exchange mechanism that allows nodes to find each other.
Overlay networks like DHTs/gossip protocols/supernodes are generally used for such a thing, but it could be as simple as a user manually entering the current IP address.
In practice reachability is a much bigger concern. NATs and Firewalls may prevent incoming connections. If both nodes cannot accept incoming connections then neither can connect to the other.
I need to deliver a lot of HTTP content (Lets say it simple - a Big storage with HTTTP Access - Similar to AWS S3)
The Bandwith needed for this excedds the Bandwith of one Server (We get 200MBit each Server and the question is not to change this)
For out Prog we need 1Gbit that woudl mean 5 Servers.
When I connect them togeter with mod_proxy then I have one Server in front which only has 200MBit. So thats not the right way.
But these Servers must be accassible from the Web with one Domain Name. Is there a possibillity to so that? Example: One gets the HTTP Request, but the Resonse comes from a different Server?
DNS Round Robin?
Different Idea?
Thanx
If the outbound network traffic is not CPU limited, you can use this open source Linux Network Balancer
http://lnlb.sourceforge.net/
The inbound network speed will remain at 200MBit, but with five nodes the maximum outbound limit is 5*200MBit.
A lot of people condemn round robin DNS, perhaps assuming that it will take a full TCP timeout to detect all failed node which is simply not the case. Its a simple way to solve the performance problem and improves availability a lot. This also helps to solve the potential bottleneck of your lan without having to go to 10gbit Ethernet which would be a requirement between a router and a load balancer for the rate of traffic you describe.
There may be scope for getting more throughput from your servers and hence only needing 3 or 4 servers rather than 5. But that's a very different question.
I want to connect more than 5 bouncers to my favourite irc network.
Unfortunately, server accepts only up to five connections from one IP.
How can i do it and is it real?
I have only one server with one IP but i have a domain with an unlimited number pf subdomains.
You could use a proxy server.
http://en.wikipedia.org/wiki/Proxy_server
Either ask the network for a connection limit exemption (which a network should be able to give you if you explain why you need it), or you'll need a second IP or a second server - there's no way around this.
With a second machine, you could set up a bouncer on that machine (such as irssi with irssi-proxy), then connect ZNC to irssi. Alternatively, you could use SSH tunnelling to route your IRC connection through another machine.
Neither method is particularly good, multiple ZNC instances on multiple machines, or an exemption is probably the best way. Talk to the network staff about it and see what they can do.
I have very little experience on this so I am asking to see if this is even possible. I have 4 different ADSL connections that each one is connected to one access point so I have 4 total different lans. I provide free hotspot on each access point (same SSID) and the user roaming from one access point to the other as they move into the area. (The area is a long road and the distance beetween each AP is about 100m).
Anyway i saw on the modems the option for dhcp relay so I am asking this.
Can I build a central server (internet accessable) with ubuntu and dhcp server on it and setup the modems to use this as DHCP server? So the user keep the same IP as it moves from one AP to the other. All adsl modems will have the same IP so the gateway will remain same for all networks. I dont know if this is good so I am asking this question just to tell me what is the best way? To build a central server or to leave each modem act as dhcp server
Because my English are not very well I hope you understand my question
Thanks a lot!
This can be done, but I don't know if it will provide any benefit to you:
User comes online from AP1, DHCP discover is received by the modem and relayed to the DHCP server, response is sent back and the user receives and binds to IP.
User crosses the threshold and changes to AP2. Because the media has changed, the user will re-discover and perform the DHCP process again. They will most likely be allocated the same address again (presuming the lease hasn't expired or been administratively removed), but you're still re-binding the IP. Because you are re-binding the IP on the User, any open TCP connections would likely be severed.
I think that this is what you're trying to avoid by allocating the same address across all devices, but please do correct me if I'm wrong.