what is the only segment in a TCP stream without the ACK bit set?why?
411846
See RFC 1072, pg 6. This describes Selective Acknowledgement and particular uses.
533325
In the TCP/IP protocol suite, data is exchanged in the form of packets. Because of the way TCP/IP performs routing, the path taken by packets can change dynamically throughout a session. This means that if Host A and B are communicating and Host A sends two packets, they could potentially take different paths to Host B, and could arrive out of order. Host B must therefore have a way to re-assemble the packets (containing the data in octets) in correct order. \n\nTCP/IP provides a way to do this using sequence numbers. Starting from an initial sequence number (ISN) that each host provides as part of the session setup, each octet is assigned a sequence number that is one larger than that of its predecessor. For example, if Host B provides 123 as the initial sequence number for its session with Host A, Host A's first octet is numbered 123, the second is numbered 124, the third is numbered 125, etc. \n\nIf someone attempts to launch an attack against another computer and the attacker can predict how a host selects ISNs, it's possible to conduct two types of attacks, known as IP address spoofing and session hijacking. The more random the ISNs are, the more difficult it is to carry out these attacks. \n\nFor related information on this problem, please visit the following Microsoft Web site: \nhttp://www.microsoft.com/technet/security/bulletin/MS99-046.asp (http://www.microsoft.com/technet/security/bulletin/MS99-046.asp)\nFor additional security-related information about Microsoft products, please visit the following Microsoft Web site: \nhttp://www.microsoft.com/technet/security/
471493
In total there is 65535 UDP/TCP ports allocated . This number comes from an unsigned 16 bit integer. 2^16-1=65535. However, the first 1024 port numbers are reserved for common applications such as ftp (20,21), ssh (22), http (80) etc. This means that for other common applications there is "only" 64511 available port numbers.\nIf you write your own TCP/IP client server application, you are not allowed to use < reserved port number. But the 64511 available ones should be enough.
871267
This may happen if you are choosing WEP 64Bit instead of WEP128Bit Key.\n\nWEP128 Bit Key is much longer than the Wep64 Bit Key.
765091
Mn is close, but there are 2 errors:\n\n1) There is no len() function.  Use strlen() instead of len().\n\n2) He didn't allocate enough memory for the sprintf to fit the entire result string in the buffer.  The line needs room to store the &#92;n (or in windows, 2 chars - cr and lf ) in addition to the null terminator.  So, his code needs to add 2 instead of 1 to the length calculation.  \n\nTaking this a little further, the number of chars should be multiplied by the sizeof(t_char), which MIGHT NOT be 1 byte if the code is destined to use unicode.\n\nChances are, this is ascii, so the multiplication is unnecessary, but it is better to be safe than sorry.  Besides, if this was production code, you'd want to be able to use the same code in both places without any need to change it.  Nothing worse than having to go back and recalculate buffer manipulation code during a port.\n\nThe above subtleties demonstrate precisely how and why it is so very easy to make a mistake in c/c++, leading to a buffer underallocation or overwrite, and hence a security hole.
600562
Okay once again..\nStringBuffer b = buf.replace(6,10,"orld");\n\nThis replaces offset 6 to 10 with world... So offset 6 in your case is W so it would be:\nHello orld\n\nNow That is correct.. Now b.delete(0, 1)\nThat deletes the 0 offset which is H! only so it would be\nello\n\nNow the total StringBuffer Contents is:\nello orld\n\n\nSee why? Remember buffers is like a memory location that stores a buffer, so treat it as global scope in that case
384081
Well, all Messneger applications do the following:\nthey use\n- TCP Protocol for authentication (LOGIN), etc\n- UDP Protocol for chatting\n\nThe difference between the 2 is that TCP guarantees the delivery of data while UDP doesn't, and thats why, in some cases, while text messaging or Voice chatting, some text &/or portions of voice conversation is omitted...\n\nHope this answers your question...
252949
It's basically one way to encapsulate data.  If you send a 1 MB transmission it is chopped into smaller bits so that it can be sent efficiently.  One way to do this is frame relay, another way is ATM.
277050
You don't need instructions for TCP/IP. TCP/IP is the communication method your computer uses to talk on the Internet. Don't mess with it at all.
99138
There is a program called Tcpview. Sometimes it will show the IP. But not always.
628097
Imagine a block of memory from 0 to N. A cyclic buffer fills from 0 towards N, and when it reaches N it starts back at 0 again.\nThis kind of buffer needs to be "serviced" (have the data removed) before new data overwrites data that hasn't been removed yet.\nThere is normally an "in" pointer for incoming data, and an "out" pointer for outgoing data, If the "out" pointer reaches the "in" pointer, the buffer is empty again. If the "in" pointer reaches the "out" pointer, you've overflowed the cyclic buffer!
102614
Mega bits and Mega bytes ??\n\n1 byte = 8 bits
763372
The transport layer usually turns the unreliable and very basic service provided by the Network layer into a more powerful one. There is a long list of services that can be optionally provided at this level. None of them are compulsory, because not all applications want all the services available. Some can be wasted overhead, or even counterproductive in some cases.\nInternet protocol suite Layer\nConnection-Oriented\n    This is normally easier to deal with than connection-less models, so where the Network layer only provides a connection-less service, often a connection-oriented service is built on top of that in the Transport layer.\nSame Order Delivery\n    The Network layer doesn't generally guarantee that packets of data will arrive in the same order that they were sent, but often this is a desirable feature, so the Transport layer provides it. The simplest way of doing this is to give each packet a number, and allow the receiver to reorder the packets.\nReliable Data\n    The underlying network may well be noisy, and the data received may not always be the same as the data sent. The Transport layer can fix this: typically by providing a checksum of the data which detects if there has been a glitch of some kind. Of course, error free is impossible, but it is possible to substantially reduce the numbers of undetected errors. This layer may also retransmit packets which have gone missing en route.\nFlow Control\n    The amount of memory on a computer is limited, and without flow control a larger computer might flood a computer with so much information that it can't hold it all before dealing with it. Nowadays, this is not a big issue, as memory is cheap while bandwidth is comparatively expensive, but in earlier times it was more important. Flow control allows the receiver to say "Whoa!" before it is overwhelmed. Sometimes this is already provided by the network, but where it is not, the Transport layer may add it on.\nByte Orientation\n    Rather than dealing with things on a packet-by-packet basis, the Transport layer may add the ability to view communication just as a stream of bytes. This is nicer to deal with than random packet sizes, however, it rarely matches the communication model which will normally be a sequence of messages of user defined sizes.\nPorts\n    Ports are essentially ways to address multiple entities in the same location. For example, the first line of a postal address is a kind of port, and distinguishes between different occupants of the same house. Computer applications will each listen for information on their own ports, which is why you can use more than one network-based application at the same time.\n\nOn the Internet there are a variety of Transport services, but the two most common are TCP and UDP. TCP is the more complicated, providing a connection and byte oriented stream which is almost error free, with flow control, multiple ports, and same order delivery. UDP is a very simple 'datagram' service, which provides limited error reduction and multiple ports. TCP stands for Transmission Control Protocol, while UDP stands for User Datagram Protocol. Other options are the Datagram Congestion Control Protocol (DCCP) and Stream Control Transmission Protocol (SCTP).\n\nSome things, such as connection orientation can be implemented at either Transport or Network layer. The idea is that the Network layer implements whatever set of options is easiest: for some underlying networks it is easiest to implement connectionless communication, while for others it is easiest to implement connection oriented communication. The Transport layer uses this simplest set of options to implement whatever combinations of options are actually desired.\n\n///
41057
Below are some simple examples of how to send "stream" data from a client and a server using the TIdTCPClient and TIdTCPServer components.  Each connection on the server is an item in the server's Binding property.  Hopefully this helps.\n\nprocedure SendFromClient(Client: TIdTCPClient; Value: string);\nvar\n  ssOut: TStringStream;\nbegin\n  ssOut := TStringStream.Create('This is a string stream.');\n  try\n    IdTCPClient1.WriteStream(ssOut);\n  finally\n    ssOut.Free;\n  end;\nend;\n\nprocedure SendFromServer(Server: TIdTCPSever; Stream: TStream);\nvar\n  Buffer: PChar;\nbegin\n  GetMem(Buffer, Stream.Size);\n  try\n    Stream.Write(Buffer[0], Stream.Size)\n    Server.Bindings[0].Send(Buffer[0], Length(Value) + 1, 0);\n  finally\n    FreeMem(Buffer, Stream.Size);\n  end;\nend;\n\nSorry, noticed a mistake...corrected.
162682
Most likely you are referring to a send only server.
1004599
Every TCP transaction involves a 3-way communication -- that is:\n- Your computer sends ("uploads") a request for a resource\n- The server receiving the request sends a response (which your computer *downloads)\n- Your computer acknowledges that the data packet was received (this is another upload operation)\n\nSo technically, whenever you post anything on a website, you have just downloaded something.\n\nCongratulations! Since you are posting on Yahoo!, your problem appears to be resolved.
1099448
Simple Mail Transport Protocol