TCP and IP are two important protocols used in networking today. Due to their importance, the Internet Protocol Suite is also commonly known as "TCP/IP"

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50% Throughput on direct connect XCOPY transfer

I have two Dell Servers with multiple gigabit network ports each. These run a sync process using XCOPY. To improve throughput and reduce overall network impact, I have dedicated a connection on each ...
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2answers
90 views

Special Routing and NAT requirement

I have a rather special routing and NAT issue which I hope I can fix somehow. Inside my company we run a supernet like 192.168.0.0/21 (192.168.0.1 - 192.168.7.254) All computers have this subnet mask, ...
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1answer
1k views

Best way to calculate optimal subnet masks for a range of IP addresses? [closed]

I thought I saw a tool like this once upon a time, but can't find it anymore... Anyone know a tool that would take a free range of IP addresses (as in start / end) and calculate a set of submasks ...
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1answer
121 views

TCP/UDP Connection States documentation

Does anyone know where to find documentation for TCP/UDP connection states? Preferably non-Microsoft with unix backing. Basically, I'm looking for more information about TCP established, TCP ...
2
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1answer
493 views

Is Winpcap able to capture all packets going through a Gigabit NIC without missing any packets?

I want to use Winpcap to capture all network packets going through a Gigabit NIC of a server. Assuming that I am able to utilize the network link up to 100%, the maximum network speed is 1000Mbps. If ...
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1answer
321 views

Way to do basic WAN optimization between two Linux servers that splits single connection into multiple parallel ones? [closed]

There are utilities on Linux that allow you to work around WAN conditions which cause you to not be able to utilize your full bandwidth. They do this by performing multiple requests in parallel (for ...
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2answers
304 views

Why tcp/ip model is being used for Developing Protocols and not OSI [closed]

why TCP/IP model is used for designing Protocols and why not OSI model,if i am not wrong OSI is the first reference model and in TCP/IP model same concept is followed but coupled with other layers. ...
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2answers
3k views

Windows Server 2008R2 - can't change or remove the default gateway

We've installed VMWare Server 2.0 on Windows 2008R2. After some time playing with it (actually only removing host-only and nat networks, and binding adapters to the specified vmnets) we've noticed a ...
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1answer
254 views

SQL Server 2008 intermitent error 40 running parallel queries

Here's our setup : We are using Red Gate SQL Multi-Script to run queries on our ~1000 databases which reside on a single SQL Server 2008. SQL Multi Script can be configured to run queries in ...
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5answers
61k views

Huge amount of TIME_WAIT connections says netstat

Okay, this is creeping me out - I see about 1500-2500 of these: root@wherever:# netstat Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 ...
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2answers
71 views

Why would a process be showing an outbound connection from a 169.254 address when there's no unconfigured adapter?

I have a system that has several network adapters, only one of which is enabled. That adapter has ipv4 only enabled and it has a single IP address. It was previously part of a team. The team was ...
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1answer
758 views

Where are my TIME_WAITs on Mac OS X?

No TIME_WAITs on Mac OS X Normally, when a TCP connection is closed, the socket on the side where close() is called first is left in the TIME_WAIT state. When one of the peers is a Mac OS X (Lion) ...
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8answers
13k views

How to find the gateway IP address in Linux

What command can you use to find the Gateway IP Address (ie. home router address) for eth0 in Linux? I need to get the IP address from a command line app to use in a shell script.
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3answers
2k views

Too Many ESTABLISHED connection from a single IP address in Apache

netstat -ntp |grep 80 shows too many ESTABLISHED connection from single IP address. Around 300 of them and it is not an attack and user is using a 2G connection to access Apache. This is the case ...
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3answers
189 views

No route to host after changing interface to static ip [closed]

I installed a Linux (Ubuntu) server inside my home LAN, initially it's automatically configured to use DHCP interface. I'm connecting to this server from another computer using that server's hostname. ...
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2answers
353 views

Why do we need logical addressing [duplicate]

Possible Duplicate: Why couldn’t MAC addresses be used instead of IPv4|6 for networking? If physical address or Mac address is unique why do we need logical addressing? This because ...
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1answer
258 views

IPv6 & ReservedPorts in Windows Server 2008 registry

I have HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ReservedPorts set to 1153-1153, but sometimes IPv6 programs get assigned this port. Is this setting for IPv4 only? Is ...
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2answers
3k views

Problems with MDNS flooding on port 5353 UDP

I am running into a big issue at a small network i manage. This network is an Apple network, with airport extremes, expresses, mac book pro's, imac's, ipads, iphones etc... I went to add something to ...
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2answers
2k views

custom route not working on windows

My windows laptop is directly connected to 192.168.1.0/24 (wireless lan). I access 10.21.0.0/16 though a router that is connected to both networks. The routing works fine with this configuration. I ...
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1answer
138 views

Sender Information Not Cached on the Receiver During an ARP Request

I'm currently trying to get my head around more advanced networking concepts. The way I am doing this is by going on one of the servers I look after as a sysadmin and running network captures to see ...
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0answers
329 views

switch OFF syn cookies

We have several servers they have public IP's, but work together (one is with Load Balancer, orther with Apache Web server, other with MySQL and so on. Most of the ports are fire-walled, so only ...
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3answers
3k views

TCP/IP communication between Hyper-V host and guests

This may be a simple one. :) I have a simple Hyper-V setup with a few guest os running. The host has 1 physical network adapter with a static IP assigned to it. The guests have network adapters ...
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4answers
113 views

Just one client bound to address and port: does it make a difference broadcast versus unicast in terms of overhead?

Scenario: I am implementing failed over for a network node, so my idea is to make the master node listens on a broadcast ip address and port. If the master node fails, another failover node will ...
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7answers
7k views

Latency in TCP/IP-over-Ethernet networks

What resources (books, Web pages etc) would you recommend that: explain the causes of latency in TCP/IP-over-Ethernet networks; mention tools for looking out for things that cause latency (e.g. ...
2
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1answer
90 views

Host data transfer limit calculations and network protocol headers

OK, this might be a really stupid question, but... I'm building a web app that utilises websockets. There's fairly rapid messaging going on, so I've been taking a look at the network traffic with ...
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1answer
830 views

Solaris TCP/IP performance tuning

I am trying to tune a high message traffic system running on Solaris. The architecture is a large number (600) of clients which connect via TCP to a big Solaris server and then send/receive relatively ...
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2answers
503 views

monitoring TCP/IP performance on Solaris

I am trying to tune a high message traffic system running on Solaris. The architecture is a large number (600) of clients which connect via TCP to a big Solaris server and then send/receive ...
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1answer
227 views

multicast streaming, too much network traffic?

I am thinking of switching our streaming servers to use multicasting instead of registering multiple clients and duplicating the streams manually on the server. It seems to work very well. However, I ...
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0answers
701 views

NIC Teaming , Multi-Homed, Active/Passive

I'm fairly new to NIC Teaming.. So I apologize if I’m not making any sense while describing this. I’ve, of course, set up plenty of simple Active/Active NIC teams for our servers without any issues ...
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2answers
902 views

Raw TCP/IP port forwarding software

I have server which IP address is whitelisted in some external system. And also, I have a few software developers with dynamic IPs which develop software and they need to connect to external system, ...
0
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1answer
409 views

Can ranges overlap in ReservedPorts?

The value ReservedPorts in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters contains a list of port ranges to reserve so the system won't assign them to programs dynamically. ...
3
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2answers
2k views

IP address used by nslookup and ping is different

I have a web server hosted in the network. It has a domain name registered. However, I also host a DNS server for the LAN. So, when someone wants to access the web server, it would check the DNS ...
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4answers
3k views

Error Connection to SQL Server using [HOSTNAME]\instance or [FQDN]\Instance, [IP]\instance working

This one's kind of weird, at least to me. I've got MSSQL server 2k5 (STD) installed on Server 2k3 R2 SP2 (on account of some legacy software that doesn't yet support x64 or Server 2008), using ...
18
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9answers
12k views

What is the OSI model and how does it apply to todays networks?

As a system administrator what should I know about the OSI model? (Rec X.200) Briefly, what are the layers and what do they do? How much do I need to know about in my day-to-day work? How does this ...
2
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1answer
176 views

Disabling Operating System TCP Management

Is there a way to disable TCP state management of OS, for example on a specific port, or on another ip or if not, disabling the whole tcp management and managing it in an application with root access? ...
3
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2answers
3k views

IIS7 hundreds of connections in CLOSE_WAIT

I have a .Net application on my IIS7 server it was working fine until I had to move it to another server. I moved the exact same code to the new server and I noticed that after some hours the ...
3
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1answer
286 views

Iproute2 tools vs conntrack tools

I have a linux box which is setup as firewall/gateway for the network. Was just wondering why ss and other iproute2 tools show much less than iptables conntrack. Is it because the router function is ...
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2answers
719 views

Can't connect to a Hyper-V VM from anywhere but the host OS

I have an unusual situation on hand where I'm able to connect to a Hyper-V guest VM from the HOST, but not from anywhere but the host. The VM is running WIn2k8R2 and has IIS installed and Remote ...
2
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3answers
635 views

Can ping server but no telnet or www

I have a NAS (iomega home media 1TB) plugged in router using 1Gb ethernet cable. Occasionally I lose access to it, I can ping it by static ip, nmap to see all open ports but can't telnet to it. Also ...
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1answer
611 views

One Windows Domain workstation can ping gateway but gets no internet access

One of the (Windows XP SP3) workstations of our Windows Domain could not access internet anymore, this problem suddenly happened overnight. The domain controllers (there are three of them) are all ...
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1answer
306 views

Linux kernel 3 TCP IP tuning

I found several resources about tuning linux TCP/IP stack parameters in /etc/sysctl.conf for high bandwidth connections, but all refer to kernel 2.6. Does anyone have suggestions about how to tune ...
14
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1answer
2k views

What am I misunderstanding about calculating MTU?

Okay, I just finished resolving a jumbo frames issue between a few Xserves, a Netgear GSM7224, and a Drobo B800i. It turned out that the Xserves (Mac OS X 10.6.8 Server) and the Drobo B800i accept the ...
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1answer
131 views

What would cause my SendMail server not to acknowledge receiving a TCP Sequence?

My TCP/IP Stack knowledge is a little rusty so please bear with me.... I have a CentOS 5.7 server with SendMail and am having seeing intermittent timeout issues sending email (particularly larger ...
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5answers
10k views

Windows 2008 Corrupt TCP/IP? (Ping access denied)

I'm having a weird problem on two Windows 2008 VMs (inside HyperV) running NLB. They were working at one point, but now TCP/IP appears to be corrupt. I cannot ping anything if logged in with my Domain ...
3
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1answer
296 views

Restricting ssh tunnel port access by group

My understanding is when creating an ssh tunnel to a remote machine, the ports become open on that machine for anyone to use and connect back to my local box (not just the user who opened the tunnel). ...
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6answers
492 views

What tools exist for learning and understanding TCP/IP more quickly?

I am trying to learn TCP/IP. Can anyone recommend some tools to help me better understand it?
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4answers
4k views

Using SAN Fiber Channel network for TCP/IP, possible?

I would like to know if it is possible to use the FC-switch (that is used for a SAN) also for TCP/IP traffic. We have servers (virtual machines) that must have a fast network for copying much data. ...
2
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2answers
208 views

Using a broadcast or network ID as src IP in PPP?

In case of PPP, are we allowed to use any IP address including broadcast & network id as the source address? For example: 192.168.1.0, 192.168.1.255? One of the customer has configured a DHCP ...
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3answers
757 views

Network device to change IP address within packets

I have an appliance with a class C IP address, for example 192.168.0.10. I can't or don't want to change this IP address. However when I connect this appliance to my network I want it to appear to ...
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1answer
432 views

Why won't sql server express 2008 service restart after I enable TCP/IP Protocol?

Whenever I enable TCP/IP connections on my SQL Server Express 2008 database server running on Windows XP SP3, I cannot restart the service, it simply states "The request failed or did respond in a ...