SNMP/No Bufferspace

[Larry Rosenman]

I have a mrtg job that runs every 5 minutes on a FreeBSD-CURRENT box and 
gets this randomly:

SNMP Error:
send_query: No buffer space available
SNMPv1_Session (remote host: "main-switch.lerctr.org" 
[192.168.200.224].161)
                   community: "lerctr"
                  request ID: 1517898706
                 PDU bufsize: 8000 bytes
                     timeout: 2s
                     retries: 5
                     backoff: 1)
  at /usr/local/lib/perl5/site_perl/SNMP_util.pm line 492.
SNMPGET Problem for ifInOctets.39 ifOutOctets.39 sysUptime sysName on 
lerctr at main-switch.lerctr.org::::::v4only
  at /usr/local/bin/mrtg line 2330.
2019-06-03 10:50:00: WARNING: Skipping host main-switch.lerctr.org as it 
does not resolve to an IPv4 address
2019-06-03 10:50:00: WARNING: no data for 
ifInOctets&ifOutOctets:lerctr at main-switch.lerctr.org. Skipping further 
queries for Host main-switch.lerctr.org in this round.
2019-06-03 10:50:00: WARNING: Skipping host sewingroomswitch.lerctr.org 
as it does not resolve to an IPv4 address
2019-06-03 10:50:00: WARNING: no data for 
ifInOctets&ifOutOctets:lerctr at sewingroomswitch.lerctr.org. Skipping 
further queries for Host sewingroomswitch.lerctr.org in this round.
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_39][_IN_] ' 
$target->[24]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_39][_OUT_] ' 
$target->[24]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_40][_IN_] ' 
$target->[25]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_40][_OUT_] ' 
$target->[25]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_41][_IN_] ' 
$target->[26]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_41][_OUT_] ' 
$target->[26]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_42][_IN_] ' 
$target->[27]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_42][_OUT_] ' 
$target->[27]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_43][_IN_] ' 
$target->[28]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_43][_OUT_] ' 
$target->[28]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_44][_IN_] ' 
$target->[29]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_44][_OUT_] ' 
$target->[29]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_45][_IN_] ' 
$target->[30]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_45][_OUT_] ' 
$target->[30]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_46][_IN_] ' 
$target->[31]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_46][_OUT_] ' 
$target->[31]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_47][_IN_] ' 
$target->[32]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_47][_OUT_] ' 
$target->[32]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_48][_IN_] ' 
$target->[33]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[main-switch.lerctr.org_48][_OUT_] ' 
$target->[33]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[sewingroomswitch.lerctr.org_1][_IN_] 
' $target->[34]{$mode} ' did not eval into defined data
2019-06-03 10:50:01: ERROR: Target[sewingroomswitch.lerctr.org_1][_OUT_] 
' $target->[34]{$mode} ' did not eval into defined data


I have:
kern.ipc.maxsockbuf=2147483648

in my sysctl.conf as suggested in a bunch of places, and the box has 
plenty (128G) of memory.

How can I debug this?


-- 
Larry Rosenman                     http://www.lerctr.org/~ler
Phone: +1 214-642-9640                 E-Mail: ler at lerctr.org
US Mail: 5708 Sabbia Dr, Round Rock, TX 78665-2106