Dynamic Host Configuration Protocol (DHCP)/Bootstrap Protocol (BootP)
Written on 10:25 by Ahmet Emir
Dynamic Host Configuration Protocol (DHCP)
assigns IP addresses to hosts. It allows easier
administration and works able-bodied in baby to alike actual ample arrangement environments. All types of
hardware can be acclimated as a DHCP server, including a Cisco router.
DHCP differs from BootP in that BootP assigns an IP abode to a host but the host’s hardware
address charge be entered manually in a BootP table. You can anticipate of DHCP as a dynamic
BootP. But bethink that BootP is additionally acclimated to accelerate an operating arrangement that a host can boot
from. DHCP can’t do that.
But there is a lot of advice a DHCP server can accommodate to a host back the host is
requesting an IP abode from the DHCP server. Here’s a account of the advice a DHCP server
can provide:
IP address
Subnet mask
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Chapter 2
Introduction to TCP/IP
Domain name
Default aperture (routers)
DNS
WINS information
A DHCP server can accord us alike added advice than this, but the items in the account are the
most common.
A applicant that sends out a DHCP Discover bulletin in adjustment to accept an IP abode sends out
a advertisement at both band 2 and band 3. The band 2 advertisement is all
F
s in hex, which looks like
this: FF:FF:FF:FF:FF:FF. The band 3 advertisement is 255.255.255.255, which agency all networks
and all hosts. DHCP is connectionless, which agency it uses User Datagram Protocol (UDP) at the
Transport layer, additionally accepted as the Host-to-Host layer, which we’ll allocution about next.
In case you don’t accept me, here’s an archetype of achievement from my accurate Ethereal analyzer:
Ethernet II, Src: 192.168.0.3 (00:0b:db:99:d3:5e), Dst: Broadcast
➥
(ff:ff:ff:ff:ff:ff)
Internet Protocol, Src: 0.0.0.0 (0.0.0.0), Dst: 255.255.255.255
➥
(255.255.255.255)
The Data Link and Arrangement layers are both sending out “all hands” broadcasts saying,
“Help—I don’t apperceive my IP address!”
Broadcast addresses will be discussed in added detail at the end of
this chapter.
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