APC SU1400XLT User Manual download pdf (Page 48)

Security Issues:

• apcupsd runs as root.

• If you have NETSERVER ON in your apcupsd.conf file (which is the default), be aware that anyone

on the network can read the status of your UPS. This may or may not pose a problem. If you don't

consider this information privileged, as is the case for many, there is little risk. In addition, if you have

a perimeter firewall or NATting router with typical settings only users on your local network access to

your UPS information. You may also restrict access using using firewall settings (see below) or TCP

Wrappers (see below).

Firewall Settings

If you are running apcupsd as an NIS server, you will need to ensure that the clients can reach it by

opening up NISPORT (default: TCP 3551) on any firewall running on the server. You may wish to

configure your firewall(s) to only allow connections from your local network or specifically from the

masters, slaves, and servers as needed.

TCP Wrappers

If your operating system does not support a host based firewall (a firewall running on the local machine)

then you may try to get some of the functionality of such a firewall with TCP Wrappers. As of apcupsd

version 3.8.2, TCP Wrappers are implemented if you turn them on when configuring ./configure

--with-libwrap. With this code enabled, you may control who may access your apcupsd via TCP

connections (the Network Information Server). This control is done by modifying the file: /etc/hosts.allow.

This code is implemented but untested. If you use it, please send us some feedback.

Configuring Your EEPROM

If you have a SmartUPS, there are depending on the UPS at least 12 different values stored in the

EEPROM that determine how the UPS reacts to various conditions such as high line voltage, low line

voltage, power down grace periods, etc.

In general, for the moment, we do not recommend that you change your EEPROM values unless

absolutely necessary. There have been several reported cases of problems setting the Low Transfer

Voltage. Consequently, if at all possible, do not attempt to change this value.

Using apctest to Configure Your EEPROM

To make the EEPROM changes with apctest you must first stop the apcupsd daemon. After apcupsd is

stopped you may invoke apctest (as root).

We recommend that you change the EEPROM as little as is absolutely necessary since it is a somewhat

delicate process that has occasionally produced problems (i.e. improper EEPROM values are displayed

after the update).

apctest will present a menu of options which are generally self-explanatory. Note that USB connections

will show a difference set of options than smart serial connections.

Maintaining Your UPS Batteries

Battery Technology

Sealed Lead Acid (SLA) batteries, otherwise known as Valve Regulated Lead Acid (VRLA) batteries, were

originally known as "dry batteries". When first introduced in the 1950s, they used a gel electrolyte. The

otherwise free acid was immobilised with a fine silica powder and formed a gel substance.

In the 1970s the technology moved to Absorbed Glass Mat (AGM) where the separators between the lead

plates are made of highly porous micro-fine glass fibres which absorb and immobilise the acid and prevent

it from spilling. A crack or hole in the casing of a VRLA battery using AGM technology will not result in a

measurable electrolyte spill. Spill containment with VRLA batteries is therefore not meaningful or

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APC SU1400XLT User Manual Page 48

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