2025-06-04, tcpip20250528.txt

# (C) David Vajda
# TCP/IP Std Uebung - auswendig
# 2025 05 28

NUL     Nullzeichen
SOH     Start of Heading
STX     Start of Text
ETB     End of Transmission Block
EOT     End of Transmission
ETX     End of Text
CR      Carriage Return
DEL     Delete
CAN     Cancel
ESC???  Escape
BS      Backspace
BEL     Bell, Klingel
VT      Vertical Tab
HT      Horizontal Tab
LF      Line Feed
FF      Form Feed
SO      Shift Out
SI      Shift In
DC1..4  Device Controll 1..4
ACK     Acknowlege
NAK     Not acknowlege

RS-232/CCITT-5

CCITT = Commitee Consultative International Telegraphique et Telephonique

CCITT-1 Baudot Code urspruenglich digitaler 5 Bit Zeichencode, synchron

jean maurice emile baudot

1 bd = 1 zeichen eines zeichenvorrats pro Sekunde

GND
RxD
TxD
RTS     Ready To Send
CTS     Clear To Send
DSR     Data Set Ready
DTR     Data Terminal Ready

Sub-D-9-Stecker: male
Sub-D-9-Buchse: female

Von Westen nach Osten
Von norden nach sueden

im norden: 5

5: GND
2: TxD
3: RxD

Terminal: Datenendgereat
Modem: datenuebertragungsgeraet

Handshaking, Flusskontrolle: Programm: Fluss, Uebertragung: Fluss
    Hardware
    Software
    Protokoll

RS-232:
    +12V/-12V

mark/space

baud-rates:
...
2200
4400
8800
...

5/6/7/8/9 bit zeichen
1 oder 2 stop bit
1 start bit
no/even/odd parity

max232
    t1in
    t2in
    t1out
    t2out
    r1in
    r2in
    r1out
    r2out

USART/UART

UART: Universal Asynchrounous Transmitter/Reciever
USART: Universal Synchrounous/asynchronous reciever transmitter

atmega8:
    UBRRH, UBRRL
    UCSRC, UCSRB, UCSRA
    UDR

    UBRRH, UBRRL: USART Baud Rate Register
    UCSRC, UCSRB, UCSRA: USART Control and Status Register
    UDR: USART Data Register

UDRE USART Data Register Empty
TXEN, RXEN: Transmit/Recieve Enabled
UCSZ1:0:USART Control and Status Register
UBS0??
URSEL: Aktivieren des RS232
    ???

TCP/IP Ports, Server
    15  netstat
    20  ftp
    21  ssh
    25  smtp
    53  dns
    80  http
    110 pop3
    143 imap
    443 https
    587 imaps?

Records, DNS
    A       IPv4 Name Record
    AAAA    IPV6 Name Record
    PTR     Pointer Record
    TXT     Text Record
    MX      Mail Exchange Record
    CNAME   Cannonical Name Record - Cannonisch - Richtschnur


TCP
    Source Port             16 Bit
    Destination Port        16 Bit
    Sequence Number         32 Bit
    Acknowlegement Number   32 Bit
    Reserved                 5 Bit
    Flags
    Data Offset
        ...
    urgent Pointer
    ... Window
    ...
    Options

IP
    Source Address              32 Bit
    Destination Address         32 bit
    TTL DSCP
    ...

Binarys:

    netstat
    telnet
    ip
    traceroute
    tracepath
    nslookup
    reversdnslookup?
    geoiplookup
    ifconfig
    ifup ifdown
    ping
    curl
    wget
    iptables

iptables:
    chain
    rule

    rule
        filter
        nat
        mangle
        raw

    chain
        INPUT
        PREROUTING
        FORWARD
        POSTROUTING
        OUTPUT

    -A  INPUT/OUTPUT/...
    -p  protocol: tcp/icmp/udp
    -d  destination Port
    -s  source Port
    --d-port
    --s-port
    -S  Source Address
    -D  Destination Address
    -j  ACTION:
            DROP
            REJECT
            ACCEPT
            LOG
            ...


files
    /etc/hosts
    /etc/interfaces

Assymetric encryption Algos
    RSA
    DSA
    EDDSA
    ECDSA

RIPDEM-160

checksum

Adler-32
Modulo
paritaet
Fletcher's Checksum
crc
md5

symmetric encryption Algo:
    AES, AES-192, AES-256
    CAMMELLIA-192, CAMMELLIA-256, CAMMELLIA-512
    BLOWFISH TWOFISH
    3DEST
    CAST5


MD2 MD4 MD5
SHA1 SHA256 SHA512 SHA384 ...

ARGON2
...