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

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7
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2answers
916 views

Linux Router Problem

I have a Linux based router with four interfaces (each with its own private subnet). When I directly connect a device directly (i.e. no switch, just a patch cable) to one interface and another device ...
0
votes
1answer
294 views

Cannot Access SQL2008 R2 instance over TCP

I have enabled Named Pipes and TCP/IP for this instance and restarted the service. I have also made sure the the port on the server is open on the firewall. I have also made sure that I have the ...
5
votes
2answers
261 views

Do I need routing protocols on a small network?

I have a small network with 10 VLANs, mostly routed via our core layer 3 switch. RIP is enabled on the core switch, but I'm in the process of adding a second router for a couple of VLANs as our core ...
2
votes
2answers
328 views

IPv6 and Hop Limit

I am reading RFC 2460 about IPv6 and it says that "the packet is discarded if Hop Limit is decremented to zero.", so that is to say that if a router decrements a packet's Hop Limit to 0, other another ...
2
votes
3answers
421 views

Linux router with 4 NICs not working

I'm setting up a Linux based router, with 4 NICs, and I can't seem to convince it to work, despite following steps suggested on various web sites. Each interface is on a separate subnet as follows: ...
0
votes
1answer
209 views

CentOS can I connect mobile and remotely from a laptop using another mobile connect to ssh or ssh -x?

Case: I placed one rack mounted server which has only intra-network activity (do not require any kind of internet access just for the service). Issues: But many times it requires remote access, in ...
4
votes
2answers
551 views

Google network architecture

I am aware that this question might be closed as "not a real question", "subjective" or even "argumentative". If this is a mistake, I am sorry. I am not good at all at networking but I'm trying to ...
0
votes
1answer
896 views

Postfix: Source IP-address

I currently have multiple network interfaces on my server. When I try to send mail, through telnet, the IP which i connect to, isn't showing up as the source ip, but the ip of eth0 is showing. I have ...
4
votes
4answers
652 views

Web server is slow on port 80 but fast on port 81

Apache is listening on port 80. I have a script doing a curl on a small static image and timing the response. It normally takes 0.04 secs but on 6 out of 10 requests it takes anywhere from 2 to 20 ...
2
votes
1answer
3k views

Netcat - Listen for Multiple UDP Connections

I'm trying to use netcat to debug SIP calls, which communicate over UDP. Is there a way to get the same netcat instance to listen to multiple UDP Connections? I've tried connecting to the same netcat ...
0
votes
3answers
139 views

my proxy server isn't visible from outside of the network [closed]

I'm writing an http proxy server (homework assignment). I got it working on my home network but i can't connect to it from the outside. I've configured the router to forward communication on the port ...
6
votes
4answers
8k views

How to find the process which causes the arp request?

When i run tcpdump in the gateway, i get a lot of arp requests originating from the gateway itself. I wonder know why this happens. How can i find the process that causes these arp requests? $ ...
2
votes
2answers
144 views

How to migrate DNS correctly

Client has DNS at a telephone company which provide emails for his domain (sudamerica.cl). I need to switch DNS in order to get control over them so I can properly set the A records for the new ...
1
vote
1answer
173 views

System MTU for SAN switch

I have a SAN with redundant cisco 2960s when I set it up a while ago I set all of the interfaces to use an MTU of 9000. I was looking at the config today and I noticed this line system mtu routing ...
0
votes
2answers
1k views

Can't connect to Web-Service running on VMware Player

I have windows 7 installed and I am running VMware player with Ubuntu as the guest OS. I installed Etherpad which runs on http://localhost:9000 in the VMware player. In the VMware player itself I can ...
0
votes
1answer
379 views

configuration of 6to4 tunnel

I've got problem with configuration 6to4 on virtual machines. I've got two machines with ubuntu. Conf. of first machine: #ip tunnel del tun6to4 #ip tunnel add tun6to4 mode sit ...
1
vote
3answers
1k views

Linux Router with Single NIC

Suppose I have a small network, with a number of VLANs as follows: VLAN1 10.1.1.0/24 VLAN2 10.1.2.0/24 VLAN3 10.1.3.0/24 VLAN routing is taken care of by the core switch, the switch ...
0
votes
3answers
606 views

Turn on a Linux machine remotely [closed]

My previous laptop is in really poor physical condition, so my plan is to leave it at home as a scraping server (accessed by ssh). How would I remotely turn it off/on? (or do anything else like ...
1
vote
1answer
6k views

Temporary failure in name resolution

I keep getting an error message whenever doing anything that requires a dns lookup on my centos server. For example: [root@15557 etc]# wget ...
0
votes
2answers
150 views

secure methods of automating file transfer via scp

Yesterday I asked a question about restricting access via ssh, and I was advised to have my machine access the data on the public workstation. As an unfortunate necessary follow-up to that, how can I ...
4
votes
3answers
6k views

Windows Server 2008 Ignores Persistent Route With Lower Metric

I have three Windows Web Server 2008 SP2 machines on a 10.100.20/24 subnet. I need to setup a persistent routing rule so that outgoing traffic to the same subnet goes through a hardware load balancing ...
7
votes
2answers
853 views

ISP grade Proxy

We are a ISP in Africa (bandwidth is expensive, more than 800 USD per Mbit). Instead of investing in more bandwidth I believe it can be worthy to invest on web proxy appliance. I prefer to use mature ...
0
votes
1answer
791 views

Isolated subnet on Vmware Workstation for testing

I need to setup a virtual testing lab to test some software updates and group policy changes. I will be using Vmware Workstation 7. I will setup a Windows Server 2008 R2 Domain ...
2
votes
1answer
140 views

OpenVPN network sharing

For some hours I'm already trying to setup a virtual private network between two physical locations (Location A, 192.168.1.0/24), and (Location B, 192.168.2.0/24). I am forced to use a tunnel instead ...
3
votes
4answers
2k views

Portable way to get list of all active network interfaces

I would like to get the list of all active network interfaces (e.g. eth0, wlan0). I assume I'll have to parse the output of ifconfig, but the formatting is different across the various OS's. Does ...
1
vote
1answer
3k views

Windows Server 2008 R2 as guest in virtualbox: make accessible from all network nodes within the subnet of my host

I want to install Exchange 2010 on a Windows Server 2008 R2 in my virtual box v4 running on my laptop (running Windows 7). Additionally I have a Windows Phone 7 on which I want to access the Exchange ...
1
vote
1answer
143 views

Function of SOH, LOH, POH in SONET

Can anyone explain what is the function of section overhead, line overhead and path overhead in SONET STS-1 frame? Why they are used? Thanks, Neel
2
votes
2answers
2k views

DD-WRT PPTP VPN problem [closed]

I try to configure a DD-WRT as a PPTP client. The VPN Server is Windows Server 2003. This is my scenario: The Windows 2003 Server has set to give to the VPN Client the 10.0.0.81 fixed IP and to ...
1
vote
1answer
139 views

Modem Question - PPPoE and PPPoA

What's the difference between PPPoE and PPPoA?
0
votes
1answer
178 views

Internet Access via CentOS box used as Router

I am having problems getting my network to play nice, despite it working previously. Here are the main system details; CentOS box as a router / firewall (firewall currently disabled while I get the ...
2
votes
2answers
792 views

load balancing, high availability for webapp setup

We have build a special interest social network and need to setup now the proper server setup for the webapp servers. We have for the webapp 5 physical server available (2xE5645 CPU, 24 GB Ram, RAID, ...
2
votes
1answer
554 views

delete broken network shortcuts from My Network Places

I am running Windows XP SP3. I have several shortcuts in My Network Places in Explorer that point to nonexistent IP addresses. I never succeed to delete them. When I do left-click on them, or ...
3
votes
1answer
267 views

Broadcast and Collision Domains

Ok...this is one very basic thing Im confused on. with regarding to hubs/routers/and switches I know hubs all contain one large collision domain (which is "bad" but can someone explain why) and a ...
0
votes
1answer
154 views

How to link 2 Cisco switches + 1 Netgear

I have servers in 2 different locations. The setup is: The 4 linksys switches are all on the same sub-network. The link between the 2 data centers are provided by the collocation company. So ...
0
votes
1answer
227 views

Network structure and topology advice

As per a few prior questions - I am in the process of splitting a server with a variety of role into individual servers with one role per server. I have now got the following servers/roles setup: ...
4
votes
3answers
753 views

Forcing the dig tool to return us answers from the root servers

When doing a dig over some site (i.e. www.nasa.gov) from different online dig tool sites(in this case, http://networking.ringofsaturn.com/Tools/dig.php and http://www.kloth.net/services/dig.php), I've ...
4
votes
3answers
455 views

Do we need a DNS server when we use OpenDNS?

I am in the process of splitting roles up from one server to 5. The current server is running as a DNS server, among other things. The DNS server just has a forwarder to the OpenDNS IP addresses and ...
0
votes
3answers
387 views

The network path was not found

I have configured the Active directory and domain in Windows Server 2008. I am trying to connect my laptop running Windows 7 to the domain. I use the "Computer Name/Domain Changes" dialog to enter ...
1
vote
2answers
2k views

Bridged mode virtualbox client not working

I have CentOS server installed in virtualbox running on windows 7 host. The CentOS client has internet access if I select NAT, but if I select 'bridged' then it has no internet access. I have to use ...
1
vote
3answers
711 views

Group Policy, Printers and Additional Domain Controller

We have a number of Windows Server 2008 R2 on our network, one is the master domain controller and another is the additional domain controller. When I setup the additional domain controller (with the ...
1
vote
1answer
11k views

Force RTMP streams playing flash to be requested via Proxy Server

I have a network squid proxy server that all our network traffic is routed through. I have a problem when a RTMP stream is viewed, flash is sending the request directly to the RTMP server and not ...
2
votes
2answers
442 views

Multiple Gateway improve performance

I have a proxy Server and a PBX server that both have their own router as a gateway. Nevertheless, the company acquired an additional more stable ISP and now I have three Internet connections. Is ...
0
votes
4answers
110 views

Windows 7: Reworking the Network

Within the next month or two, we're going to be getting brand-new computers at my office, and it's going to be my responsibility to set them up and network them. I've not messed with networking under ...
2
votes
2answers
346 views

What is 17.10.13.204 (Apple?) doing that's always blocked as port-scanning traffic?

I've just recently noticed an IP address that has been showing up in our SonicWall logs on a pretty frequent basis. Throughout the course of an average day, we'll see around 100 dropped packets ...
0
votes
2answers
162 views

How does a network update its IP lookup when a PC switches between wired/wireless?

We have PC's that switch IP's when they go between wired and wireless access to our network. Unfortunately when a PC goes from wireless to wired, all the other computers on the network are not made ...
0
votes
2answers
97 views

Network Bottleneck Question

I have a VMware ESXi host that runs 2 virtual machines, and we will be adding two more to it. One VM is our main DC/DHCP/DNS/Fileshare/SVN server, and the other is a development testing VM. The two ...
1
vote
1answer
681 views

eth0 doesn't start after interfaces modification

Just installed Ubuntu Server 10.04 on VMWare ESXi 4.0.0 (201167) and changed the interfaces file. My (modified) interfaces file looks like this: auto lo iface lo inet loopback iface eth0 inet ...
3
votes
2answers
321 views

Odd results from ping

When I run this on an Ubuntu box: sudo ping google.com -c 25 -l 25 I get about 1 line back every 2 seconds despite the fact that it should (if I'm reading things correctly) send out all 25 packets ...
1
vote
2answers
625 views

Linux bridge redundancy

I make heavy use of Linux Bridges (brctl) as I have a Xen environment. At the minute, only one physical NIC is connected to the bridge (There are many virtual NICs for the Xen VMs though). In order to ...
0
votes
1answer
111 views

Networking Vlan [closed]

How many Vlan create a particular Switch. If a Switch has 48 prots then we can create 48 Vlan or higher.