Re: What makes BOOTP routable, but RARP isn't?

ipnwsec wrote:
Hi,

Bootp runs above the UDP Layer i.e it is an application layer protocol,
which has IP header and IP address info in the Bootp packet, so a
router /layer3 device which has bootp relay finctionality will router
it to the dhcp server.

But RARP is a layer below IP so it does not have any IP header, and if
you see routiing is a layer 3 functionality.

let me know if you have any more questions.

Thanks,
Sunil
http://geocities.com/sunil3112000

Tauno Voipio wrote:
ihatecrappymail@xxxxxxxxx wrote:
Hi all,

I am not sure if this is the right place to ask this, but I couldn't
find better match so I was hoping some of you all might be able to help
me understand something.

I am reading about the TCP/IP protocol suite and how RARP (and maybe
ARP, I'm not sure, maybe someone can clarify for me) are not routable,
but BOOTP is. My question is why? They both come from clients that do
not know their IP address and they both send out broadcast messages
correct? So, what is the difference between them?

Any help in this area is greatly appreciated!


ARP and RARP are link-level protocols, and as such
their forwarding does not understand anything about
IP routing, which is one level above the link layer.

BOOTP runs on top of UDP which runs on top of IP,
and this is subject to normal IP routing rules.

--

Tauno Voipio
tauno voipio (at) iki fi


Thanks for the info guys. Just one other question. I understand now
that it is because BOOTP is wrapped in IP that makes it capable for
routers to route it. But, what I don't understand is that the
Destination IP is a broadcast address (255.255.255.255). I thought
broadcast addresses were not routed? So how does a workstation find a
DHCP server if it is not on the same segment (or does the DHCP server
HAVE to be on the same segment, which I thought that not having to have
a DHCP server on every segment was one of that advantages of using DHCP
in the first place)?

Thanks for your help guys! I am slowly starting to understand :)

.

Relevant Pages

  • Re: What makes BOOTP routable, but RARP isnt?
    ... Bootp runs above the UDP Layer i.e it is an application layer protocol, ... But RARP is a layer below IP so it does not have any IP header, ...
    (comp.os.linux.networking)
  • How to assign IP address to NDIS driver?
    ... layer and pass it to COM port via PPP protocol. ... though there are no real ethernet protocol running). ... since the IP address of NIC is accquired from DHCP server. ... How can I assign IP address to NDIS driver? ...
    (microsoft.public.development.device.drivers)
  • Re: PXE boot debian-installer
    ... The DHCP server running on the router assigns addresses in the ... This will only work if you can set the router to ignore bootp requests and the Lenny DHCP to accept only bootp request (ignore booting requests) or visa versa. ... From the documentation the default Debian DHCP server will by default ignore "bootp" requests. ...
    (Debian-User)
  • Re: Need freeware Bootp server app
    ... They either support just BootP or BootP/DHCP. ... > that only support BootP will NOT get an IP stack from a DHCP server. ... Attached is a sample configuration file for the HP J6039C. ...
    (microsoft.public.win2000.general)
  • Re: DNS and DHCP diskless Server
    ... > wanted to put it to work as a small DNS and DHCP Server for Tania and Catia. ... > Can I make Catia a BOOTP server with a small partition to boot David so I ... I'd look into dnsmasq. ...
    (Fedora)
Loading