Hub
Layer 1
Repeater
Layer 1
NIC
Layer 1
VPN Concentrators
Layer 1
Cables
Layer 1
Bit
Layer 1
Switches
Layer 2
Frame
Layer 2
Routers
Layer 3
Packet
Layer 3
Segment
Layer 4
Data
Layers 5, 6, 7
Application layer
OSI 7, dod 4
SMTP
Layer 7
HTTP
Layer 7
DHCP
Layer 7
DNS
Layer 7
LDAP
Layer 7
IMAP
Layer 7
FTP, TFTP
Layer 7
TCP, UDP
Layer 4
SSL, TLS
Layer 4
IPV4, IPV6
Layer 3
IGMP
Layer 3
IPSec
Layer 3
RIP
Layer 3
ARP
Layer 2
MAC
Layer 2
Port 53
DNS
Port 20-21
FTP data/control
Port 22
Sftp (using ssh), ssh, scp
Port 25
SMTP
Port 23
Telnet
Port 88
Kerberos
Port 137-139
Netbios
Port 143
Imap4
Port 161
SNMP
Port 389
LDAP
Port 500
Ipsec
Port 989 or 990
FTPS (using ssh or tls)
Syn Flood
Layer 4
Fraggle
Layer 4 - exploits UDP
Ping Floods/Ping of Death/Loki
Layer 3
Smurf Attack
Layer 3 - Spoofs Source Address
Tunneling
Layer 2
Kernal Proxy Firewall (Gen 5)
Layer 7
Stateful Firewall (Gen 3)
Layer 4 (5?) inspects)
Static/Stateless Firewall (Gen 1)
Layer 3 (blocks or allows entire protocol - all or nothing)
BGP (path vector protocol)
Layer 4/dod layer 2