Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -18,3 +18,4 @@ snmpwalk -v2c -c public -ObentU 10.10.10.10 .1.3.6.1.2.1.1.2 >> hostname.snmpwal
 snmpwalk -v2c -c public -ObentU 10.10.10.10 .1.3.6.1.4.1.9.9.171.1.2.3.1 >> hostname.snmpwalk
 snmpwalk -v2c -c public -ObentU 10.10.10.10 .1.3.6.1.4.1.9.9.171.1.3.2.1 >> hostname.snmpwalk
 ```
+If you need to _hide_ your public IP-addresses you can replace them by private IPs (like 271.217.222.21 replaced by 10.1.1.1 for excample), as long as the snmpwalk stays valid.