Enterasys Networks Security Router X-PeditionTM - Manual (Page 44)

Utilizing the Command Line Interface
2-8 Managing the XSR
RAI checks each DLCI, up to 30, on a given interface for a Bootp response, an rDNS server and a
TFTP server with a configuration file. The first DLCI that accomplishes this will be chosen. If the
connection fails, RAI will reset itself and restart at Phase 1, next media-type.
If the DLCI does not have all of the correct servers and responses, the next DLCI on that interface
is queried. The last DLCI in the list will loop around to the first DLCI to be continued indefinitely
in persistent mode and for five minutes in non-persistent mode as set by the
netload command.
A node with no startup-config will default to persistent (forever) mode. A node with no Serial
NIM card installed will abort RAI processing immediately and proceed to the login prompt after
executing a local startup-config file if it exists.
While in RAI mode, inverse ARP, pings, and other packets entering the port may be optionally
responded to depending on the phase of the process. It is not recommended that you rely on the
proper response to these packets.
Bootp Client
The Bootp client sends up to five broadcast bootp requests with the MAC address of the first
Ethernet port in the node as the client's unique hardware address. The MAC address is chosen this
way for compatibility with bootp servers to be associated based on the hardware address. In
newer FR/routers which provide Bootp server functionality inside the FR configuration, this
hardware address field is ignored and responded to locally with static mapping.
In the Bootp response, the boot file provided is ignored by the client. The IP address assigned by
the Bootp server in the bootp reply is used as the client's IP address.
Reverse DNS Client
The rDNS client sends a broadcast request with the discovered IP address from bootp as the
source. This rDNS request occurs five times before quitting. The broadcast relies on the central site
router to have a helper IP address configured to forward to the correct server. Use the
ip
helper-address command to set the DNS server IP address.
TFTP Client
The TFTP client broadcasts a request for the hostname-config file first. The TFTP server responds
with a unicast reply, from then on unicast is used for both the client and server. The TFTP
broadcast relies on the central site router to have a helper IP address configured on the
corresponding interface to forward to the correct server.
If the file is not found or is read-protected, the TFTP client will try the additional file types shown
below. Once all the names have been exhausted, the next DLCI from FR will be tried.
• Hostname-confg
• Hostname.domain-confg
• Hostname.cfg
• Hostname.domain.cfg
• enterasys-confg
• enterasys.cfg
If the server does not respond, RAI tries the next DLCI, renegotiating bootp and rDNS as before.
Frame Relay (Central Site)
At the central site, the node is a fully configured router to accept broadcast bootp requests from a
remote router. If bootp service is to be provided by an external server then omit this parameter.