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Concepts
TCP/IP
2-13
The SLIP section of the Server Configuration chapter covers SLIP setup and other restrictions.
2.7.7 Simple Network Management Protocol (SNMP)
The ETS supports the SNMP network protocol, which allows hosts on the network to query nodes for
counters and network statistics and change some parameters on those nodes. The form of these requests is
documented by RFC 1098. The list of items that can be queried and/or set and the type of data used, such
as integer and string, are both documented in various Management Information Bases (MIBs). MIBs cover
a variety of things, such as parallel port status, counters, and IP address resolution tables.
The ETS supports the following MIBs:
MIB-II (RFC 1213)
System, Interface, Address Translation, IP, ICMP, TCP, and UDP, but not the
EGP group.
Parallel MIB (RFC 1660)
All parallel devices.
Serial MIB (RFC 1659)All Serial devices.
Character MIB (RFC 1318)
All character-oriented devices.
The ETS will respond to queries for unknown MIBs with a “not in MIB” error to the requesting host. RFC’s
1065, 1066, and 1098 offer additional information on SNMP queries and the structure of the MIBs. See Set/
Define SNMP on page 12-98 for more information about configuring MIB usage.
Traps are sent to a host when an abnormal event occurs on the ETS. The ETS can generate limited forms
of three SNMP traps. It will generate a Coldstart trap when it first boots, and a Linkup trap when the
startupfile (if any) has been read from a host and normal operation commences. If a startupfile has been
configured but the download fails, the ETS will send an Authentication trap. In all three cases, the trap will
be directed to the IP address of the ETS’s loadhost. The ETS will not generate traps for any other cases.
Note:
To disable traps, define the Loadhost as “0.0.0.0” and reboot the server. See Set/
Define Server Loadhost on page 12-70 for syntax.
The ETS has a local SNMP security table to restrict or prevent unauthorized SNMP configuration.
2.7.8 Reverse Telnet (RTEL)
When a server provides a service to a LAT host, the connection is often referred to as Reverse LAT. Reverse
Telnet allows a UNIX host to initiate connections to the ETS in much the same way. It is called Reverse
Telnet because “normal” connections are logins from a server to a host.
Your ETS comes with special software to add RTEL functionality to your UNIX host. RTEL connections
can be made through a back-end program for a printer, or through a named pipe. For example, you can print
files from your UNIX host to a printer attached to the ETS through your host’s lp or lpr print system. ETS
services do not care what hosts are using them. Multiple jobs from any of the supported protocols can be
queued simultaneously on any service.