as already mentioned, I have not modified iptables in regard to the communication with the management nic on our APC ups. It was just working by using dom0 default settings.
@dougs
Why using "pcnet" as device instead of snmp? You need to specify a username and a pass passphrase.
If you go with snmp it is quite simple to archive.
[17:17 IT1XCP-NG-SLAVE1 apcupsd]# apcaccess
APC : 001,046,1126
DATE : 2023-01-25 17:17:30 +0100
HOSTNAME : IT1XCP-NG-SLAVE1
VERSION : 3.14.14 (31 May 2016) redhat
UPSNAME : IT1USV1
CABLE : Ethernet Link
DRIVER : SNMP UPS Driver
UPSMODE : Stand Alone
STARTTIME: 2022-12-11 14:08:12 +0100
STATUS : ONLINE
LINEV : 231.0 Volts
LOADPCT : 9.0 Percent
BCHARGE : 100.0 Percent
TIMELEFT : 84.0 Minutes
MBATTCHG : 45 Percent
MINTIMEL : 25 Minutes
MAXTIME : 0 Seconds
MAXLINEV : 233.0 Volts
MINLINEV : 226.0 Volts
OUTPUTV : 231.0 Volts
SENSE : Unknown
DWAKE : 12000 Seconds
DSHUTD : 240 Seconds
DLOWBATT : 2 Minutes
LOTRANS : 161.0 Volts
HITRANS : 253.0 Volts
RETPCT : 25.0 Percent
ITEMP : 26.0 C
ALARMDEL : 5 Seconds
BATTV : 218.0 Volts
LINEFREQ : 50.0 Hz
LASTXFER : Automatic or explicit self test
NUMXFERS : 1
XONBATT : 2022-12-18 16:58:19 +0100
TONBATT : 0 Seconds
CUMONBATT: 1 Seconds
XOFFBATT : 2022-12-18 16:58:20 +0100
LASTSTEST: 2022-12-18 16:58:19 +0100
SELFTEST : OK
STESTI : 336
STATFLAG : 0x05000008
MANDATE : 10/11/08
BATTDATE : 02/01/13
NOMOUTV : 230 Volts
EXTBATTS : 1
FIRMWARE : 477.18.W
END APC : 2023-01-25 17:18:09 +0100
[17:18 IT1XCP-NG-SLAVE1 apcupsd]#