Networks Xavier Martorell-Bofill 1 Ren Serral-Graci 1 Universitat - - PowerPoint PPT Presentation
Networks Xavier Martorell-Bofill 1 Ren Serral-Graci 1 Universitat Politcnica de Catalunya (UPC) May 26, 2014 Introduction Servers Services Lectures System administration introduction 1 Operating System installation 2 User management
1Universitat Politècnica de Catalunya (UPC)
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servicename port/protocol alias list echo 7/tcp echo 7/udp systat 11/tcp users systat 11/udp users ftp-data 20/tcp ftp-data 20/udp # 21 is registered to ftp, but also used by fsp ftp 21/tcp ftp 21/udp fsp fspd ssh 22/tcp ssh 22/udp telnet 23/tcp telnet 23/udp # 24 - private mail system smtp 25/tcp mail smtp 25/udp mail domain 53/tcp domain 53/udp http 80/tcp www www-http http 80/udp www www-http
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147.83.159.200 192.168.12.1/24 .2 .3 .4 .5
Port 22, 25, 80 Port 22 Port 25, 80
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$ cat /etc/xined.conf includedir /etc/xinetd.d $ cat /etc/xined.d/ftp service ftp { socket_type = stream wait = no user = root server = /usr/sbin/vsftpd log_on_success += HOST DURATION log_on_failure += HOST disable = no }
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int read(int fd, ... ... b = read(8, ... ... int read(int fd, ...
Stub Implementation
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d e m a n a r s e r v e i p
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Crida RPC Resultat Client Portmapper Server Registrar servei
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/etc/resolv.conf: search ac.upc.edu nameserver 147.83.33.45 www.google.com
Servidor DNS Local a.root-server b.root-server
internic.net ... www.google.com? .com
.com
iana.org alldomains.com www.google? google www? www NS3.google.com
google.com
DNS: RFCs 1034/1035
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Avoids repeating the same query
Avoids going up to the root servers too often Avoids some steps of the iterative search
Each query returns different values: Round Robin or ”geographical“ criteria $ nslookup www.google.com Name: www.google.com Address: 212.106.221.23 Name: www.google.com Address: 212.106.221.27 Name: www.google.com Address: 212.106.221.25 ...
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$ cat /etc/bind/named.conf
directory "/var/cache/bind"; forwarders { 147.83.159.217; }; auth-nxdomain no; # conform to RFC1035 listen-on-v6 { any; }; }; zone "cluster.craax.upc.edu" { type master; file "/etc/bind/cluster.zone"; }; zone "1.1.10.in-addr.arpa" { type master; file "/etc/bind/cluster.rev"; };
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$ cat /etc/bind/cluster.zone $TTL 604800 @ IN SOA
20101220 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; @ IN NS gandalf $ORIGIN cluster.craax.upc.edu. gandalf IN A 10.1.1.1 boromir-1 IN A 10.1.1.2 $ cat /etc/bind/cluster.rev $TTL 604800 @ IN SOA
20101220 ; Serial 604800 ; Refresh 86400 ; Retry 2419200 ; Expire 604800 ) ; Negative Cache TTL ; @ IN NS gandalf $ORIGIN cluster.craax.upc.edu. 1 IN PTR gandalf.cluster.craax.upc.edu. 2 IN PTR boromir-1.cluster.craax.upc.edu.
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ddns-update-style none;
allow booting; allow bootp; default-lease-time 600; max-lease-time 7200; authoritative; subnet 192.168.1.0 netmask 255.255.255.0 { range dynamic-bootp 192.168.1.172 192.168.1.254; range 192.168.1.2 192.168.1.171; filename "pxelinux.0";
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ddns-update-style interim; key DHCP_UPDATER { algorithm HMAC-MD5.SIG-ALG.REG.INT; secret pRP5FapFoJ95JEL06sv4PQ==; }; zone ac.upc.edu. { primary 192.168.1.1; key DHCP_UPDATER; }
key DHCP_UPDATER { algorithm HMAC-MD5.SIG-ALG.REG.INT; secret pRP5FapFoJ95JEL06sv4PQ==; }; zone ac.upc.edu. { type master; file "ac.zone"; allow-update { key DHCP_UPDATER; }; }; ...
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Client de mail Complet
MUA
Client de mail Simple
MUA
Servidor de Mail (SSMTP)
MSA
Servidor de Mail (SMTP)
MTA
Servidor de Mail (SMTP)
MTA
Client de Mail Simple
MUA mbox
Mail Classification
DA
Mail Storage
DA
Client de mail Complet
AA/MUA SSMTP SMTP SMTP SMTP POP3/IMAP
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OS NFS Client ...
read/write ... OS NFS Server N F S P r
shared disk
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OS NFS Client OS NFS Server shared disk local disk / /usr /home /home
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/ master(rw) trusty(rw,no_root_squash) /projects proj*.local.domain(rw) /usr *.local.domain(ro) @trustedgroup(rw) /home/joe pc001(rw,all_squash,anonuid=150,anongid=100) /pub (ro,insecure,all_squash)
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192.168.1.31 Internet 88.40.135.97 (wlan0) VPN 192.168.1.200 (tun0) 192.168.1.30 192.168.1.32 192.168.1.33
Ctrl F n Alt Alt Gr Ctrl Shift Z X C V B N M , . / A S D F G H J K L ; ' Q W E R T Y U I O P [ ] 1 2 3 4 5 6 7 8 9Internet 147.83.159.97 (eth0) VPN 192.168.1.1 (tun0)
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