diff --git a/2-IOC-deployment.md b/2-IOC-deployment.md
index 1e09b8ae079431850bbbc6725e2fee73a17b27a0..4b85ca7a5007bfae8149052fb15caed2e907e82d 100644
--- a/2-IOC-deployment.md
+++ b/2-IOC-deployment.md
@@ -203,6 +203,14 @@ make: *** [xxxApp.install] Error 2
 ```
 </details>
 
+<details>
+<summary>what does this mean?</summary>
+
+This error message indicates that the linker (ld) is unable to find two libraries: net and pcap. When building your IOC (Input/Output Controller) using the make command, the linker is responsible for resolving and linking all the required libraries.
+The -l flag is used to specify libraries that need to be linked. In this case, the linker is looking for net and pcap. However, it is unable to locate these libraries, which results in the error.
+
+</details>
+
 ### 2.7 Resolve build error #2
 
 Tell the build system the net (and pcap) libraries aren't installed.