DNS ?, TCP Segment, IP Header, Ethernet Frame - TCP-IP

This is a discussion on DNS ?, TCP Segment, IP Header, Ethernet Frame - TCP-IP ; Pardon if this duplicates itself... Road Runner servers seem to drop the first post to news groups until it's posted a second time and then they show both with 15 to 30 minute difference between posts... Application: DNS/SMTP/POP3/telnet Presentation: Images, ...

+ Reply to Thread
Results 1 to 6 of 6

Thread: DNS ?, TCP Segment, IP Header, Ethernet Frame

  1. DNS ?, TCP Segment, IP Header, Ethernet Frame

    Pardon if this duplicates itself... Road Runner servers seem to
    drop the first post to news groups until it's posted a second time
    and then they show both with 15 to 30 minute difference between
    posts...

    Application:
    DNS/SMTP/POP3/telnet <- what is the packet here called?
    Presentation:
    Images, text, data presentation, mpg, mp3, wav, etc <= file formats
    Session:
    NFX, RPC, SQL <= query information (?)
    Transport:
    TCP headers/UDP headers (port numbers) <= headers/segments
    Network:
    IP packets/IPX packets (ip details, source/destination) <= packets/routing
    Data Link:
    MAC addresses <= frames/framing
    Physical:
    wire, hubs, repeaters <= binary

    I'm guessing that the stuff at the application layer gets called
    request and response headers (at least for an http session).
    Are there any other names for the information at the Application
    Layer? And anyone able to direct me into right area so as to
    pull the information out of the data at this layer? For instance, I
    want to get to the DNS name out of this layer of information
    (Microsoft Windows API).

    Thanks much.

    --
    Jim Carlock
    Post replies to the group.




  2. Re: DNS ?, TCP Segment, IP Header, Ethernet Frame

    In article ,
    "Jim Carlock" wrote:

    > Pardon if this duplicates itself... Road Runner servers seem to
    > drop the first post to news groups until it's posted a second time
    > and then they show both with 15 to 30 minute difference between
    > posts...
    >
    > Application:
    > DNS/SMTP/POP3/telnet <- what is the packet here called?
    > Presentation:
    > Images, text, data presentation, mpg, mp3, wav, etc <= file formats
    > Session:
    > NFX, RPC, SQL <= query information (?)
    > Transport:
    > TCP headers/UDP headers (port numbers) <= headers/segments
    > Network:
    > IP packets/IPX packets (ip details, source/destination) <= packets/routing
    > Data Link:
    > MAC addresses <= frames/framing
    > Physical:
    > wire, hubs, repeaters <= binary
    >
    > I'm guessing that the stuff at the application layer gets called
    > request and response headers (at least for an http session).
    > Are there any other names for the information at the Application
    > Layer? And anyone able to direct me into right area so as to
    > pull the information out of the data at this layer? For instance, I
    > want to get to the DNS name out of this layer of information
    > (Microsoft Windows API).


    They're called whatever the author of the specification of the
    application layer protocol feels like calling it. Common terms are
    request/response, command/result, and query/reply. But not all
    applications fall into this model, sometimes it's just data, like the
    data connection in FTP or the stream in TELNET.

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

  3. Re: DNS ?, TCP Segment, IP Header, Ethernet Frame

    "Jim Carlock" asked:
    > Application:
    > DNS/SMTP/POP3/telnet <- what is the packet here called?
    >
    > I'm guessing that the stuff at the application layer gets called
    > request and response headers (at least for an http session).


    "Barry Margolin" replied:
    > They're called whatever the author of the specification of the
    > application layer protocol feels like calling it. Common terms are
    > request/response, command/result, and query/reply. But not all
    > applications fall into this model, sometimes it's just data, like the
    > data connection in FTP or the stream in TELNET.


    What about Application Layer headers? I just didn't see a
    particular name for these things in my CISCO book, or earlier
    networking books (1990ish).

    My first attempts at messing with Microsoft's ActiveX Winsock
    control doesn't seem to relay this information.

    I'm digging into creating my own control at the moment based
    upon the Winsock API (ws2_32.dll). I'm seeing Apache using
    ws2_32.dll API. Am I heading in the right direction here, or might
    Apache be hiding something? The incoming HTTP requests, get
    accepted and the DNS name in the request gets extracted where
    Apache then runs through the httpd.conf file to deliver the
    appropriate content from an appropriate folder. I don't want to
    issue a DNS query(? "query" doesn't sound right, seems to
    imply an outgoing request to get the information). I want to grab
    the DNS details out of the initial TCP request to connect.

    Dump of file ApacheCore.dll

    WS2_32.dll
    6FF972F4 Import Address Table
    6FF99000 Import Name Table
    0 time date stamp
    0 Index of first forwarder reference

    Ordinal 11 (inet_addr)
    Ordinal 115 (WSAStartup)
    Ordinal 116 (WSACleanup)
    12 WSADuplicateSocketA
    3D WSASocketA
    Ordinal 151 (__WSAFDIsSet)
    Ordinal 2 (bind)
    Ordinal 13 (listen)
    Ordinal 1 (accept)
    Ordinal 21 (setsockopt)
    Ordinal 22 (shutdown)
    Ordinal 14 (ntohl)
    Ordinal 5 (getpeername)
    Ordinal 12 (inet_ntoa)
    Ordinal 52 (gethostbyname)
    Ordinal 51 (gethostbyaddr)
    Ordinal 9 (htons)
    Ordinal 8 (htonl)
    Ordinal 16 (recv)
    Ordinal 10 (ioctlsocket)
    Ordinal 19 (send)
    Ordinal 18 (select)
    Ordinal 112 (WSASetLastError)
    Ordinal 111 (WSAGetLastError)
    Ordinal 23 (socket)
    Ordinal 3 (closesocket)
    Ordinal 4 (connect)
    Ordinal 57 (gethostname)
    Ordinal 6 (getsockname)
    Ordinal 15 (ntohs)

    Thanks for the initial reply Barry.

    --
    Jim Carlock
    Post replies to the group.



  4. Re: DNS ?, TCP Segment, IP Header, Ethernet Frame

    In article <4sIPg.137$jf2.134@tornado.tampabay.rr.com>,
    "Jim Carlock" wrote:

    > "Jim Carlock" asked:
    > > Application:
    > > DNS/SMTP/POP3/telnet <- what is the packet here called?
    > >
    > > I'm guessing that the stuff at the application layer gets called
    > > request and response headers (at least for an http session).

    >
    > "Barry Margolin" replied:
    > > They're called whatever the author of the specification of the
    > > application layer protocol feels like calling it. Common terms are
    > > request/response, command/result, and query/reply. But not all
    > > applications fall into this model, sometimes it's just data, like the
    > > data connection in FTP or the stream in TELNET.

    >
    > What about Application Layer headers? I just didn't see a
    > particular name for these things in my CISCO book, or earlier
    > networking books (1990ish).


    They're just called "headers".

    >
    > My first attempts at messing with Microsoft's ActiveX Winsock
    > control doesn't seem to relay this information.


    I don't understand what this has to do with anything. What does what
    you call something in prose descriptions have to do with how you write
    an application?

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

  5. Re: DNS ?, TCP Segment, IP Header, Ethernet Frame

    "Barry Margolin" asked:
    > I don't understand what this has to do with anything. What does
    > what you call something in prose descriptions have to do with
    > how you write an application?


    Wasn't getting very far with the search engines in trying to figure
    out a way to get the DNS header out of a Winsock connection.
    I'm still reading all sorts of information about the using winsocks.
    I'm slowly getting closer to what I need to know, though.

    --
    Jim Carlock
    Post replies to the group.



  6. Re: DNS ?, TCP Segment, IP Header, Ethernet Frame

    In article <3t3Qg.252$YA5.103@tornado.tampabay.rr.com>,
    "Jim Carlock" wrote:

    > "Barry Margolin" asked:
    > > I don't understand what this has to do with anything. What does
    > > what you call something in prose descriptions have to do with
    > > how you write an application?

    >
    > Wasn't getting very far with the search engines in trying to figure
    > out a way to get the DNS header out of a Winsock connection.
    > I'm still reading all sorts of information about the using winsocks.
    > I'm slowly getting closer to what I need to know, though.


    Maybe you need to start over, and ask the right questions. I'm still
    responding to your original post, where you asked what the packets and
    headers are called when you're talking about different layers of the IP
    stack. This has nothing to do with how you program network applications.

    --
    Barry Margolin, barmar@alum.mit.edu
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
    *** PLEASE don't copy me on replies, I'll read them in the group ***

+ Reply to Thread