UNIX operacinės sistemos

V. TCP/IP įrankiai. SSH naudojimas

Simonas Kareiva

2014 m. rudens semestras

Paskaita #5 – I dalis

Įvadas į TCP/IP bei OSI. IP adresas

IP ir MAC adresai

Darbas su UNIX OS tinkle

Komandos ping ir traceroute

Komandos arp, ifconfig ir route

TCP/IP

Duomenų perdavimo protokolų rinkinys (HTTP / FTP / DNS / …)

Sukurta 1973-1974, įdiegta 1983

Abstrakcijos lygiai (žr. toliau)

Enkapsuliacija

OSI modelis

Teoriškai

Kompiuteris 2

Maršruti-

zatorius

Maršruti-

zatorius

Kompiuteris 1

Praktiškai

Kompiuteris 2

Maršruti-

zatorius

Maršruti-

zatorius

Kompiuteris 1

Maršruti-

zatorius

Maršruti-

zatorius

Maršruti-

zatorius

Kaip vyksta komunikacija?

Ethernet

Palydovinis

ryšys / optika /

etc.

WiFi

Aplikacija

Transportas

Tinklas

Sujungimas

Aplikacija

Transportas

Tinklas

Sujungimas

Tinklas

Sujungimas

Tinklas

Sujungimas

IP adresas ir kaukė

192.168.1.112/22

11000000.10101000.00000001.11100000

255.255.252.0

192.168.1.0 - ?

192.168.3.225 - ?

Užduotis

IP adresas yra 10.250.1.48/19

Klausimai:

Kokia yra tinklo kaukės išraiška pilnu formatu?

Kiek daugiausiai kompiuterių galima sujungti į tokį tinklą?

Kokios tai klasės IP adresas?

Atsakymas - ipcalc

> ipcalc 10.250.1.48/19Address: 10.250.1.48 00001010.11111010.000 00001.00110000Netmask: 255.255.224.0 = 19 11111111.11111111.111 00000.00000000Wildcard: 0.0.31.255 00000000.00000000.000 11111.11111111=>Network: 10.250.0.0/19 00001010.11111010.000 00000.00000000HostMin: 10.250.0.1 00001010.11111010.000 00000.00000001HostMax: 10.250.31.254 00001010.11111010.000 11111.11111110Broadcast: 10.250.31.255 00001010.11111010.000 11111.11111111Hosts/Net: 8190 Class A, Private Internet

dar vienas IP užrašymo būdas (sh)

#!/bin/shIPTONUM (){IP=$1; IPNUM=0for (( i=0 ; i<4 ; ++i )); do((IPNUM+=${IP%%.*}*$((256**$((3-${i}))))))IP=${IP#*.}doneecho $IPNUM}

NUMTOIP (){echo -n $(($(($(($((${1}/256))/256))/256))%256)).echo -n $(($(($((${1}/256))/256))%256)).echo -n $(($((${1}/256))%256)).echo $((${1}%256))}

Adresų klasės

Klasė

Pirmas oktetas dvejetainėje sistemoje

Pirmas oktetas nuo-iki

Tinklą identifikuoja

Tinklų skaičius

A 0XXXXXXX 0 - 127 a. 27 = 128

B 10XXXXXX 128 - 191 a.b. 214 = 16,384

C 110XXXXX 192 - 223 a.b.c. 221 = 2,097,152

MAC adresas

08:00:20:d1:b0:0a080020 – Sun Microsystems Inc.d1b00a – unikalus gaminio ID

MAC / IP ryšys

DHCPStatinis DHCPDinaminis DHCP

Darbas tinkle su UNIX OS

talk jonas@developers.firma.lt

lynx www.delfi.lt

echo paskambink | mail –s svarbu evelina@pardavimai

ping 192.168.0.1

ifconfig

ifconfig

> ifconfig eth0 Link encap:Ethernet HWaddr 00:22:15:88:9c:93 inet addr:82.135.156.42 Bcast:82.135.156.255 Mask:255.255.255.0 inet6 addr: fe80::222:15ff:fe88:9c93/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:2038944517 errors:0 dropped:0 overruns:0 frame:0 TX packets:2634746425 errors:0 dropped:0 overruns:0 carrier:1 collisions:0 txqueuelen:1000 RX bytes:592322463 (592.3 MB) TX bytes:3453432517 (3.4 GB)

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:5318385 errors:0 dropped:0 overruns:0 frame:0 TX packets:5318385 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2254159344 (2.2 GB) TX bytes:2254159344 (2.2 GB)

ping

> ping 24.93.4.206PING 24.93.4.206 (24.93.4.206): 56 data bytes64 bytes from 24.93.4.206: icmp_seq=0 ttl=240 time=157.010 ms64 bytes from 24.93.4.206: icmp_seq=1 ttl=240 time=151.762 ms64 bytes from 24.93.4.206: icmp_seq=2 ttl=240 time=314.532 msping: sendto: Network is downping: sendto: Network is downping: sendto: Network is down^C--- 24.93.4.206 ping statistics ---6 packets transmitted, 3 packets received, 50% packet lossround-trip min/avg/max/stddev = 151.762/207.768/314.532/75.524 ms

traceroute> traceroute cisco.netacad.nettraceroute to cisco.netacad.net (128.107.229.50), 30 hops max, 40 byte packets 1 gw.ep.lt (82.135.156.254) 0.966 ms 0.940 ms 0.926 ms 2 212-59-21-193.static.telecom.lt (212.59.21.193) 2.727 ms 2.716 ms 2.703 ms 3 213-190-60-93.telecom.lt (213.190.60.93) 2.892 ms 2.880 ms 2.868 ms 4 war-b3-link.telia.net (213.248.85.89) 11.790 ms 11.779 ms 11.766 ms 5 hbg-bb2-link.telia.net (80.91.251.217) 37.136 ms 37.124 ms 37.112 ms 6 ldn-bb2-link.telia.net (80.91.249.14) 41.709 ms ldn-bb2-link.telia.net (80.91.250.151) 41.859 ms ldn-bb2-link.telia.net (80.91.254.7) 41.842 ms 7 ash-bb1-link.telia.net (80.91.251.209) 123.663 ms 123.964 ms ash-bb1-link.telia.net (213.248.65.210) 125.426 ms 8 192.205.34.209 (192.205.34.209) 122.910 ms 123.278 ms * 9 cr1.wswdc.ip.att.net (12.122.135.14) 196.349 ms 195.994 ms 195.979 ms10 cr2.phlpa.ip.att.net (12.122.4.53) 197.221 ms 199.154 ms 199.135 ms11 cr2.cl2oh.ip.att.net (12.122.2.209) 215.193 ms 213.361 ms 213.550 ms12 cr1.cl2oh.ip.att.net (12.122.2.125) 213.099 ms 221.672 ms 221.645 ms13 cr1.cgcil.ip.att.net (12.122.2.205) 222.744 ms 222.733 ms 222.720 ms14 cr1.sffca.ip.att.net (12.122.4.121) 221.392 ms 221.377 ms 221.366 ms15 gar1.sj2ca.ip.att.net (12.123.15.1) 205.537 ms 203.746 ms 203.730 ms16 12.118.124.10 (12.118.124.10) 228.697 ms 228.684 ms 228.673 ms17 sjck-dmzbb-gw1.cisco.com (128.107.239.9) 190.264 ms 190.251 ms 190.652 ms18 sjc12-dmzbb-gw1-g1-37.cisco.com (128.107.224.165) 302.883 ms 302.868 ms 302.650 ms19 sjc12-dmzdc-gw1-gig5-2.cisco.com (128.107.224.22) 303.049 ms 303.037 ms 303.025 ms20 * * *21 * * *22 * * *

arp

> arp -an? (82.135.156.222) at 00:c0:02:2a:4e:6d [ether] on eth0? (82.135.156.16) at 00:15:60:57:06:cd [ether] on eth0? (82.135.156.83) at 00:0e:0c:4e:62:f8 [ether] on eth0? (82.135.156.84) at 00:06:29:39:63:c3 [ether] on eth0? (82.135.156.6) at 00:80:a3:8c:0d:72 [ether] on eth0? (82.135.156.88) at 00:11:d8:94:a9:4a [ether] on eth0? (82.135.156.21) at 00:18:f3:87:31:17 [ether] on eth0? (82.135.156.15) at 00:0e:a6:34:37:a1 [ether] on eth0? (82.135.156.23) at 00:0c:f1:ed:c8:56 [ether] on eth0? (82.135.156.55) at 00:10:5a:5a:06:f1 [ether] on eth0? (82.135.156.254) at 00:30:48:88:d9:1e [ether] on eth0? (82.135.156.201) at 00:08:02:ef:fa:a4 [ether] on eth0

route

> route -nKernel IP routing tableDestination Gateway Genmask Flags Metric Ref Use Iface193.219.94.168 82.135.156.254 255.255.255.255 UGH 0 0 0 eth0193.219.94.141 82.135.156.254 255.255.255.255 UGH 0 0 0 eth082.135.156.0 0.0.0.0 255.255.255.0 U 0 0 0 eth00.0.0.0 82.135.156.254 0.0.0.0 UG 100 0 0 eth0

Maršrutizavimas

Kompiuteris 2

172.16.0.2/28

Router 3

Router 1

Kompiuteris 1192.168.1.1/24

Router 2

Kompiuteris 3192.168.3.1/2

4

Internetas

II dalis - kas yra SSH?

SSH - Secure SHell

Nuotolinių komandų vykdymas

SSL šifravimas

Prievadų nukreipimasX aplinkos prievadų nukreipimas (X-forwarding)

SSH – Secure SHell

ssh uosis.mif.vu.lt

ssh user1234@uosis.mif.vu.lt

ssh –l user1234 uosis.mif.vu.lt

ssh –l user1234 uosis.mif.vu.lt –p 222

ssh –l user1234 uosis.mif.vu.lt –p 222 who

ssh –X –l user1234 uosis.mif.vu.lt –p 222 xterm

SCP – secure copy

scp user@host:/path/file /local/file

scp /local/file user@host:/path/

scp user@host1:/file user@host2:/file

scp * user@host

Privatūs ir vieši raktaiSiuntėjas

Gavėjoviešas raktas

LABAS :)

Gavėjoprivatusraktas

LABAS :)

(*&#$()*@#)(&#!

#^&$

ssh-keygen# ssh-keygenGenerating public/private rsa key pair.Enter file in which to save the key (/root/.ssh/id_rsa): id_rsa1Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in id_rsa1.Your public key has been saved in id_rsa1.pub.The key fingerprint is:79:29:18:f5:6b:35:85:cb:98:6b:be:86:00:04:c4:0c root@myhost

Kaip elgtis toliau? Pvz:

# ssh b13.vu.ltEnter passphrase for key '/root/.ssh/id_rsa':

man sshd

AUTHORIZED_KEYS FILE FORMAT

AuthorizedKeysFile specifies the file containing public keys for public

key authentication; if none is specified, the default is

~/.ssh/authorized_keys. Each line of the file contains one key (empty

lines and lines starting with a ‘#’ are ignored as comments).

Known hosts

# ssh root@b13.vu.ltThe authenticity of host 'b13.vu.lt (193.219.94.176)' can't be established.RSA key fingerprint is a2:f9:5e:50:17:ca:86:b1:97:58:96:31:f2:d2:8a:93.Are you sure you want to continue connecting (yes/no)? noHost key verification failed.#

# ssh root@b13.vu.ltThe authenticity of host 'b13.vu.lt (193.219.94.176)' can't be established.RSA key fingerprint is a2:f9:5e:50:17:ca:86:b1:97:58:96:31:f2:d2:8a:93.Are you sure you want to continue connecting (yes/no)? yesWarning: Permanently added 'b13.vu.lt,193.219.94.176' (RSA) to the list of known hosts.Password:

Kai pasikeičia host key…

# ssh root@b13.vu.lt@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!Someone could be eavesdropping on you right now (man-in-the-middle attack)!It is also possible that the RSA host key has just been changed.The fingerprint for the RSA key sent by the remote host is3f:1b:f4:bd:c5:aa:c1:1f:bf:4e:2e:cf:53:fa:d8:59.Please contact your system administrator.Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.Offending key in /home/user/.ssh/known_hosts:3RSA host key for b13.vu.lt has changed and you have requested strict checking.Host key verification failed.#

Prievadų nukreipimas

ssh –R [bind_address:]port:host:hostport

ssh -L [bind_address:]port:host:hostport

Saugumasanti-sec:~/pwn/xpl# ./0pen0wn -h xx.yy.143.133 -p 22

[+] 0wn0wn – anti-sec group [+] Target: xx.yy.143.133 [+] SSH Port: 22

[~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>]

sh-3.2# export HISTFILE=/dev/null

sh-3.2# iduid=0(root) gid=0(root)groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)

sh-3.2# uname -aLinux xx.yy.net 2.6.24.5-grsec-hostnoc-4.0.0-x86_64-libata#1 SMP Mon Aug 25 15:56:12 EDT 2008 x86_64 x86_64 x86_64 GNU/Linux