Do 8. Mai 11:10:43 CEST 2025 - tcpip20250501 txt

 
(C) David Vajda
2025-05-01
TCP/IP auswendig

ASCII Code
    NUL         Nullzeichen
    SOH         Start of Heading
    STX         Start of Text
    ETX         End of Text
    ETB         End of Transmission Block
    EOT         End of Transmission
    HT          Horizontal Tab
    VT          Vertical Tab
    LF          Line Feed
    FF          Form Feed
    CR          Carriage Return
    BS          Backspace
    DEL         Delete
    CAN         Cancel
    ESC         Escape
    ACK         Acknowlege
    NAK         Not Acknowlege
    DC1         Device Controll 1
    DC2         Device Controll 2
    DC3         Device Controll 3
    DC4         Device Controll 4
    SO          Shift Out
    SI          Shift In

RS-232
    5   GND
    2   TxD         Transmit Data
    3   RxD         Recieve Data

        DTR         Data Terminal Ready
        DSR         Data Set Ready
        CTS         Clear 2 Send
        RTS         Ready 2 Send

USART - Universal Synchronous Reciever and Transmitter

UBRR                USART Baud Rate Register
UBRRH UBRRL
UCSRC UCSRB UCSRA   USART Controll and status register
UDR                 USART Data Register

TXEN                Transmit Enable
RXEN                Recieve Enable
UDRE                USART Data Register Empty
UCSZ1:UCSZ0         USART Character Size
....

Baud-Rate
    ....
    1200
    2400
    4800
    9400
    ....

5, 6, 7, 8, 9 Data Bits
1 or 2 Stop Bit
1 Startbit
no even odd parity

Baud: Ein Zeichen eines Zeichenvorrats pro Sekunde

Jean Maurice Emile Baudout

sub-d-9 stecker
    maennchen stecker
    weibchen buchse

mark
space ...

max232
t1in
t2in
t1out
t2out
r1in
r2in
r1out
r2out

application layer
    15  netstat
    20  ftp
    21  ssh
    25  smtp
    53  dns
    80  http
    110 pop3
    143 smtp
    443 https
    586 imaps

dns records
    A           IPv4 Name Ressource Record
    AAAA        IPv6 Name Ressource Record
    MX          mail xChange Record
    PTR         Pointer Record
    CNAME       Cannonical Name Record
    TXT         Text Record

TCP-Pakete
    IP-Destination Address
    IP-Source Address
    Sequence Number (4 Byte)
    Acknowlgement Number (4 Byte)
    Data Offset
    Flags
        FIN
        SYN
        ACK
        ...
    Recieved Window
    Urgent Pointer
    Options
IP
    TTL
    DSCP
    IHL
    TOS
    Source Port
    Destiniation Port
    ...

iptables
    table
    chain

    table
        filter
        nat
        mangle
        raw
    chain
        INPUT
        PREROUTING
        FORWARD
        POSTROUTING
        OUTPUT
    -A  CHAIN
    -j  ACTION
            DROP
            ACCEPT
            REJECT
            LOG
            ...

    -p protocoll
            icmp/udp/tcp
    -S SOURCE IP ADDRESS
    -D DESTINATION IP ADDRESS
    --source-port
    --destination-port
    -d-port
    -s-port

NAT - Network Address Translation


    telnet
    netstat
    ip
    ifconfig
    ping
    traceroute
    tracepath
    trace
    iptables
    whois
    geoiplookup

IDEA 3DEST CAST5 TWOFISH
BLOWFISH
AES AES-192 AES-256
CAMMELIA-192
CAMMELIA-256
CAMMELIA-512

Assymetrisch
    RSA
    DSA
    DERSA oder DSA??
    DCRSA ???

Checksum
    Modulo
    paritaet
        gerade
        ungerade
        keine
        anzahl bits gerader paritaet
        ungerader
    fletcher's checksum
    adler-32
    arithmetisches mittel
    crc
    md5