Transmission Control Protocol (TCP) and Internet Protocol (IP) provide end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination.

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TCP\IP Packet Signature - how to identify such data packets?

I know of a program that can "carve" (look for) TCP IP Packets from raw binary data. The results it presents are the source and destination MAC addresses, the source and destination IP addresses and a ...
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558 views

How does the browser know which packet is the response to a specific request?

I am sniffing the in/out packets over TCP. I have some GET output, but I want to know which of the packets is the input? How does the browser determine this? Simpler explaination: I'm sniffing and I ...
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1answer
7k views

Not able to ping remote server

I am getting Request Time Out on pinging a remote server. I am on my laptop connected to the this server via Remote Desktop Connection. tried but still not able to ping it. I just want to ellaborate ...
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999 views

DNS server keeps changing from Auto to Manual

A friend at a company I know has a fairly new Windows 7 laptop. She was complaining that the "internet doesn't work". After looking at it the first time, in Wireless > Status > Properties > ...
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Determining what process has bound a port (without listening) on Windows

If I want to find out what process is listening on what socket, I can use netstat/TCPview and will immediately see it. However, it is possible to bind to an address without listening. If this is done, ...
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How do I log outgoing TCP connections from my computer?

I'm trying to track down a problem where something is causing my active directory account to get locked out. I think that I could figure it out if I can log all connections to 2 specific servers. I ...
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174 views

Please get me outta here.. Stubborn APIPA

Any one please help me.. I am getting an APIPA since three days.. I did all the steps mentioned in answers to this question. Still they did not resolve my problem. At last I formatted whole of my ...
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1answer
122 views

Limiting upstream rates for web in Ubuntu 12.10

I found this thread, but am hesitant when it comes to screwing with my network settings. What I want to do is limit the rate that people can download files from my webserver remotely. LAN ...
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3answers
591 views

XP to Win 7 via ethernet cable. No routers, no wireless. They can't ping each other

I've got a windows XP machine and a windows 7 laptop connected by an ethernet cable. The xp has static ip address 169.254.84.221 and the windows 7 has 169.254.84.220. both subnet masks 255.255.255.0. ...
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1answer
178 views

Why are there limitations on TCP segment size?

I have a question about the limitations on the segment size in the transport layer. Since the data has to get to the lower layers why will it be fragmented? Finally the data is sent in bits at the ...
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2answers
837 views

Is there free software that can convert serial input messages to TCP/IP packets?

There is a serial port that can receive text messages from the external device. Now I want to pass these messages to a special software. But that software can only receive TCP/IP packet. For example, ...
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89 views

Is it possible to see content of TCP/IP connection?

This is a bit weird. I want to see the content of all TCP/IP connections coming in/out of the system. Is any of this possible on the same machine? I know I won't be able to see encrypted content but ...
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6k views

How to reset Host Only Adapter Networking for Oracle VirtualBox VM Manager

My Host Only Networking stopped working, how do I reset it ? I tried disabling and re-enabling Local Area Connection and VirtualBox Host-Only Network but VirtualBox Host-Only Network is still ...
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1answer
438 views

IP checksum offload

I recently updated to Windows 8 and get alot of invalid packet transfers. It says "Ip checksum offload?" (Wireshark) and most of my packets get lost. The checksum is 0x00. I also updated my NIC ...
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547 views

TCP-IP versus TCP-IP over VPN

What are the advantages and disadvantages of a TCP-IP connection over VPN opposed to a regular TCP-IP connection? I am interested mainly in speed and security! Thank you.
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904 views

No route to host after changing interface to static ip

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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1answer
732 views

Change the default route without affecting existing TCP connections

Let's say I have two public network addresses on my server: one NAT through an ISP (192.168.99.0/24), and a VPN through a different ISP (192.168.1.0/24), already configured with a per-host route to ...
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1answer
128 views

How does the internet protocol handle network card numbers?

I know that data packets sent over the internet carry the source and destination IP address, so that the protocol can route the data to the correct destination and keep track of the source address of ...
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1answer
55 views

DHCP/routing oddness

I have a Squid proxy server on my network that is connected to the DHCPd server (commodity router) through a commodity switch. If there is a break in the connection (eg router needs to be rebooted) I ...
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Are Segments, Packets and Frames the same size if we ignore headers?

I've looked for some explanation about the differences between Segments, Packets and Frames, and from what I read: Segment is the original data + Transport Layer header. Packet is a Segment + ...
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389 views

Service to transparently use an HTTP CONNECT proxy on Linux

As our corporate network provides an HTTP CONNECT proxy for people who need to connect to the outside world, and as every Linux application needs to be set up specially to use it, I was thinking about ...
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1answer
1k views

User defined mapping hostname-to-address without root privileges

Is it possible to define a mapping hostname to IP address in Linux without root access (ie modify /etc/hosts) nor a DNS server ?
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1answer
218 views

Is it possible to figure out which http request generated the corresponding response

I am using iptables to listen to tcp (http) packets. I am filtering out INPUT responses containing a matching string. Is it possible to know which http request generated the response. Assuming 10 ...
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Outgoing VPN PPTP: How to check if TCP port 1723 and GRE protocol port 47 are blocked or not in Windows 7?

I am trying to connect to a VPN Server (BestUKVPN) but I'm failing each time I try. I get a "691 error" but the username and password are OK. I searched and I am told that "port 1723" or 'GRE ...
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Disable access to TCP/IP and DNS Network Settings on Windows 7

here's my question: i have a desktop pc Windows 7 powered with two accounts with administrative rights. One of those is used by my brother. I study abroad so i need to be able to connect to my ...
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1answer
841 views

What is protocol suite?

I came across protocol suite in Internet Protocol suite, and after I searched for it I found: http://en.wikipedia.org/wiki/Protocol_stack#General_protocol_suite_description which explains protocol ...
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562 views

TCP/IP Netbios fail; Dependant service “NetBT” not installed

I've been hit by zeroaccess virus last week, it corrupted the internet connection and dns system. I cleaned everything and everything is working fine except pppoe connectins, they fail with Error 720 ...
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3k views

TCP Optimizer for OS X?

Does anyone know of a utility similar to SpeedGuide.net's TCP Optimizer or some other way to accomplish the same thing on Mac OS X (preferably with Snow Leopard)?
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1answer
700 views

MITM attack, Replay Attack, TCP Session Hijacking [closed]

I was going over the internet reading about types of attacks on a computer system and I can not differentiate between MITM, Replay and TCP Session Hijacking. They appear to be the same. Sniff the data ...
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1answer
325 views

LPR Utility for Windows 98

I'm trying to print to a network printer through TCP/IP in windows 98, however, windows 98 does not support printing to a TCP/IP port, so I read that I can do it through something called LPR. Where ...
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Windows keeps using a preferred DNS server?

I have trouble using Panera WiFi, and I finally tracked down the problem: Every time I reboot, Windows resets my TCP/IP settings for my wireless adapter to use a specific DNS server, instead of ...
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2answers
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IP Routing / Forwarding

I have an older program that I use a lot and in order to work properly it has to connect to a time sever (199.211.133.139), for some reason, I am no longer to ping this time server and the program ...
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Simple way to open Port for Transmission for a Mac Snow Leopard

I am a complete noob when it comes to TCP/IP, but would like to open up my port for the Transmission bit torrent client on Snow Leopard Mac. Also, I am based in the UK if that has any relevance.
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252 views

My wifi only allow me to use http with proxy-auth, can I use other program which use other protocol?

My school offers students WiFi which only able to use browser or other program which use only http and support proxy-authentication with BASIC Auth. For other program such as windows live messenger, ...
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1answer
264 views

How configure OMRON (V750 RFID Reader) via browser-based interface?

I have a OMRON V750-series UHF RFID System. I'm trying to access it in a browser via IP address 192.168.1.200. However, I can not gain access to it. Do I need to change my TCP/IP config?
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What layer of the TCP/IP network does ARP belong to? [closed]

I'm working my way through the Sams teach yourself TCP/IP book and it say's that the Address Resolution Protocol belongs at the Internet layer. Is this true? Other sources claim it is a Network ...
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4answers
201 views

If people transfer a lot of data on the local network can Internet connection become slow?

At my work there are at least 40 people sharing the same internet connection link over the same switch that is used both to internet access and local traffic of large file. People here usually use ...
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1answer
684 views

Mac OS X TCP/IP fingerprint obfuscator

For several reasons, I need to either prevent my OS X machine from showing up as an OS X machine in TCP/IP fingerprinting, or make it show up as, say, a Linux machine. Is there an OS X program out ...
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1answer
117 views

Need to split up packets and rebuild again at destination

Cant go into too much details here for various reasons but here's what I've got. I've a host which replies to a terminal with a receipt containing info of what items have been purchased at the ...
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1answer
66 views

Corrupted data from terminal to Host

Ive got a terminal which sends data to a host that is wrapped with <stx> and <etx>. However when it enters the network it always has 5/6 bytes of junk data in place of the <stx> and ...
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1answer
645 views

Replace sensitive IP addresses in Wireshark with XXX.XXX.XXX.XXX

What would be an easy way to replace a sensitive IP address in a Wireshark packet capture with XXX.XXX.XXX.XXX? When I export the pcap in txt or csv I can no longer import it into Wireshark.
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1answer
317 views

How far a loopback packet sent from an application layer goes on TCP/P layers?

Assuming that I want to check if my ethernet card is working fine, if I send a ping from a cmd on Windows, how far the sent packet will go? I mean, the packet will fall down over all the TCP/IP layers ...
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1answer
13k views

How can I disable any TCP/IP port on a Windows 7 machine?

I need help on finding out how to disable any particular TCP/IP port on a Windows box whenever a need arises. I googled before posting the question and I got links to articles mentioning only ...
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0answers
230 views

Mounting an NFS share with udp or mntudp options

According to the documentation of NFS client on Mac OS X 10.7 user can specify following options: udp Use UDP transport protocol. and mntudp Force the mount protocol to use UDP transport, ...
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2answers
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Tampering TCP data on a Windows application

Is there an application where I can run another application and it will allow me to see and more important manipulate the TCP data sent to another server? I'm using Wireshark to view the data, but I ...
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3answers
4k views

Why was 169.254.x.x chosen as self-assigned IP? [closed]

Were there any particular reasons that 169.254.x.x was chosen as self-assigned IP? Its binary form doesn't look nearly as "whole number-ish" as other commonly used IPs like 127.0.0.1 or 192.168.0/1.1. ...
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How to get a Port to listen on Windows 7?

I have followed the step by step instruction to open a port on Windows 7, setting both Inbound Rules and Outbound Rules to following specification: Protocal Type: TCP Local Port: 55000 Remote Port: ...
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1answer
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Open port in Window 7 for local client-server development and debugging

I am writing a C# console application for Windows 7 that can send and listen to packets (client or server). Since I only have one computer, I will have to debug and test my code locally. I first ...
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1answer
540 views

Very slow hostname resolution in Windows XPe

Hopefully a simple question to answer. I've built an XP Embedded image, and it takes from between 17 and 25 seconds for me to resolve to an IP when I ping google.com. Once it gets the IP address, ...
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1answer
897 views

Router/modem TG580v2 giving weird results

In my setup, I have the Thomson's TG580v2 router/modem, my PC connected to it via cable, and AppleTV, iPad and iPhone connected wirelessly. First issue: AppleTV can't find my PC unless it is ...