How do you find whether the application leaks memory or not

You have a powerful tool called valgrind. Get the customer to install the appropriate debug packages. If it is net-snmp, install the correct net-snmp debuginfo packages

I will show two examples here, one for net-snmp and httpd

net-snmp
# valgrind -v --leak-check=full --show-reachable=yes --log-file=snmpd-memchk /usr/sbin/snmpd -f -Lsd -Lf /dev/null -p /var/run/snmpd.pid -a


httpd
# valgrind -v --leak-check=full --show-reachable=yes --log-file=httpd-memchk /usr/sbin/httpd -X


Allow the process/daemons to run for a day or more. Stop the valgrind process using CTRL-C and then attach the resultant file. The information would be collected in httpd-memchk. file. What you see here is basically the leak summary


Valgrind output
==3623== LEAK SUMMARY:
==3623== definitely lost: 1,754,671 bytes in 4,074 blocks.
==3623== indirectly lost: 1,321,068,200 bytes in 38,549 blocks.
==3623== possibly lost: 12,860,528 bytes in 251 blocks.
==3623== still reachable: 18,011,981 bytes in 133,360 blocks.
==3623== suppressed: 0 bytes in 0 blocks.

before you take any decision, Please consult with a senior engineer