diff --git a/notes/计算机网络 - 目录.md b/notes/计算机网络 - 目录.md
index 4e20a585..b1908011 100644
--- a/notes/计算机网络 - 目录.md	
+++ b/notes/计算机网络 - 目录.md	
@@ -15,7 +15,7 @@
 - Kurose J F, Ross K W. 计算机网络：自顶向下方法（第 7 版）[M]. 机械工业出版社, 2018.
 - Stevens W R. TCP/IP 详解 卷 1：协议 [M]. 机械工业出版社, 2006.
 - [Active vs Passive FTP Mode: Which One is More Secure?](https://securitywing.com/active-vs-passive-ftp-mode/)
-- [Active and Passive FTP Transfers Defined - KB Article #1138](http://www.serv-u.com/kb/1138/active-and-passive-ftp-transfers-defined)
+- [Active and Passive FTP Transfers](https://support.solarwinds.com/SuccessCenter/s/article/Active-and-Passive-FTP-Transfers)
 - [Traceroute](https://zh.wikipedia.org/wiki/Traceroute)
 - [ping](https://zh.wikipedia.org/wiki/Ping)
 - [How DHCP works and DHCP Interview Questions and Answers](http://anandgiria.blogspot.com/2013/09/windows-dhcp-interview-questions-and.html)