*Arpanet
*switched network
*TCP/IP
*spread in the 90's
*strict procedure how things are done
*communication between layers
*clearly defined interfaces
*data encapsulation
*example
*Application
*Transport
*Network
*Physical / Data link
from wikipedia
*not much of a concern for us.
*different topologies (ethernet, wirless, DSL, modem etc)
*this is about the physical connection
*here the bits are shifted.
*how many Volt represent a 1, how many a 0
*ethernet address (HWaddr in Hex format)
*IP ICMP
*IPv4 32bit written in dotted decimal notation
*65.212.180.178
*different classes
A starts with 0 B starts with 10 C starts with 110 D starts with 1110 |
*although outdated it roughly specifies the network and host part.
*Common now is the CIDR (Classless InterDomain Routing)
192.168.10.3/24 |
this actually stands for
11000000 10101000 00001010 00000011 11111111 11111111 11111111 00000000 |
private networks that are not routed
10.0.0.0 - 10.255.255.255 (10/8 prefix) 172.16.0.0 - 172.31.255.255 (172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) |
localhost 127.0.0.0/8
"network addresses" ending with 0
"broadcast addresses" ending with 255
routing
nat
configuration
connectionless
media-streaming
makes sure every packet arrives
if it didn't arrive, it will request it again
ftp-data-transfer
*connections through ports
*well known ports can be found in /etc/services
~$ cat /etc/services # Network services, Internet style # # Note that it is presently the policy of IANA to assign a single well-known # port number for both TCP and UDP; hence, officially ports have two entries # even if the protocol doesn't support UDP operations. # # Updated from http://www.iana.org/assignments/port-numbers and other # sources like http://www.freebsd.org/cgi/cvsweb.cgi/src/etc/services . # New ports will be added on request if they have been officially assigned # by IANA and used in the real-world or are needed by a debian package. # If you need a huge list of used numbers please install the nmap package. tcpmux 1/tcp # TCP port service multiplexer echo 7/tcp echo 7/udp discard 9/tcp sink null discard 9/udp sink null systat 11/tcp users daytime 13/tcp daytime 13/udp netstat 15/tcp qotd 17/tcp quote msp 18/tcp # message send protocol msp 18/udp chargen 19/tcp ttytst source chargen 19/udp ttytst source ftp-data 20/tcp ftp 21/tcp fsp 21/udp fspd ssh 22/tcp # SSH Remote Login Protocol ssh 22/udp telnet 23/tcp smtp 25/tcp mail time 37/tcp timserver time 37/udp timserver rlp 39/udp resource # resource location nameserver 42/tcp name # IEN 116 whois 43/tcp nicname tacacs 49/tcp # Login Host Protocol (TACACS) tacacs 49/udp re-mail-ck 50/tcp # Remote Mail Checking Protocol re-mail-ck 50/udp domain 53/tcp # name-domain server domain 53/udp mtp 57/tcp # deprecated tacacs-ds 65/tcp # TACACS-Database Service tacacs-ds 65/udp bootps 67/tcp # BOOTP server bootps 67/udp bootpc 68/tcp # BOOTP client bootpc 68/udp tftp 69/udp gopher 70/tcp # Internet Gopher gopher 70/udp rje 77/tcp netrjs finger 79/tcp www 80/tcp http # WorldWideWeb HTTP www 80/udp # HyperText Transfer Protocol ....snip.... |
DNS
HTTP
SSH
sample output of ifconfig
eth0 Link encap:Ethernet HWaddr 00:19:D1:93:AE:EA inet addr:192.168.10.1 Bcast:192.168.10.255 Mask:255.255.255.0 inet6 addr: fe80::219:d1ff:fe93:aeea/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:100 RX bytes:0 (0.0 b) TX bytes:3345 (3.2 KB) Base address:0x30c0 Memory:90300000-90320000 eth1 Link encap:Ethernet HWaddr 00:80:48:51:A5:31 inet addr:192.168.0.100 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::280:48ff:fe51:a531/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:3364 errors:0 dropped:0 overruns:0 frame:0 TX packets:2897 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3753263 (3.5 MB) TX bytes:488792 (477.3 KB) Interrupt:21 Base address:0xe800 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:74 errors:0 dropped:0 overruns:0 frame:0 TX packets:74 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8537 (8.3 KB) TX bytes:8537 (8.3 KB) |
output of ip route
192.168.0.0/24 dev eth1 proto kernel scope link src 192.168.0.100 192.168.10.0/24 dev eth0 proto kernel scope link src 192.168.10.1 default via 192.168.0.1 dev eth1 metric 100 |
output of ping
ping 65.212.180.178 PING 65.212.180.178 (65.212.180.178) 56(84) bytes of data. 64 bytes from 65.212.180.178: icmp_seq=1 ttl=50 time=396 ms 64 bytes from 65.212.180.178: icmp_seq=2 ttl=50 time=420 ms 64 bytes from 65.212.180.178: icmp_seq=3 ttl=50 time=394 ms --- 65.212.180.178 ping statistics --- 4 packets transmitted, 3 received, 25% packet loss, time 3010ms rtt min/avg/max/mdev = 394.577/403.996/420.659/11.838 ms |
output of tracepath
tracepath 65.212.180.178 1: 192.168.0.100 (192.168.0.100) 0.188ms pmtu 1492 1: 192.168.1.2 (192.168.1.2) asymm 36 4.262ms 2: 192.168.1.1 (192.168.1.1) asymm 102 5.671ms 3: 59.92.64.1 (59.92.64.1) asymm 4 119.448ms 4: 218.248.255.10 (218.248.255.10) 141.537ms 5: 218.248.255.10 (218.248.255.10) asymm 4 136.279ms 6: 220.227.53.238 (220.227.53.238) 160.888ms 7: 62.216.145.81 (62.216.145.81) asymm 17 433.441ms 8: so-6-0-0.0.cjr01.ldn004.flagtel.com (62.216.128.145) asymm 16 432.633ms 9: 82.195.188.21 (82.195.188.21) asymm 14 411.295ms 10: sl-bb22-lon-8-0.sprintlink.net (213.206.128.60) asymm 13 418.883ms 11: sl-bb20-nyc-2-0.sprintlink.net (144.232.9.163) asymm 13 433.378ms 12: sl-bb26-nyc-6-0.sprintlink.net (144.232.13.9) asymm 14 415.121ms 13: 144.232.8.194 (144.232.8.194) asymm 15 427.211ms 14: tbr1.n54ny.ip.att.net (12.122.81.10) asymm 22 425.951ms 15: cr1.n54ny.ip.att.net (12.122.16.161) asymm 21 442.912ms 16: cr1.cgcil.ip.att.net (12.122.1.190) asymm 20 429.262ms 17: cr1.st6wa.ip.att.net (12.122.31.162) asymm 19 439.363ms 18: tbr1.st6wa.ip.att.net (12.122.23.154) 445.856ms 19: gbr1.st6wa.ip.att.net (12.122.12.158) asymm 17 440.989ms 20: gar1.ptdor.ip.att.net (12.123.44.121) asymm 15 422.986ms 21: 12.118.177.66 (12.118.177.66) asymm 13 421.216ms 22: po1.ir1.cvo2.kattare.net (204.13.9.2) asymm 14 420.901ms 23: ground1.kattare.com (65.212.180.178) asymm 15 437.003ms reached Resume: pmtu 1492 hops 23 back 15 |