An error similar to the following can be found in the DB2 Diag log that may be caused by the DB2 agent monitoring the DB2 instance.
YYYY-MM-DD-HH.MM.SS.SSSSSSS-240 IXXXXXXXX LEVEL: Error
PID : XXXXXXXX TID : 1 PROC : db2
INSTANCE: INSTANCENAME NODE : 000
HOSTNAME: MYHOSTNAME.MYDOMAIN.COM EDUID : 1
FUNCTION: DB2 UDB, command line process, clp_start_bp, probe:3
MESSAGE : CLP frontend unable to get REQUEST queue handle
DATA #1 : Hexdump, 4 bytes 0xXXXXXXXXXXXXXXXX : XXXX XXXX
Ensure that the /etc/resolv.conf file has permissions 644 (in Linux/Unix/AIX)
Confirm that the DNS can resolve the hostname (in the error above it is listed as MYHOSTNAME).
Add the hostname to the /etc/hosts file (or Windows hosts file) to what the HOSTNAME variable returns