Introduction

# Windows 傳遞最佳化使用mDNS(UDP 5353)進行節點探索
Windows Delivery Optimization uses UDP 5353(mDNS) for peer discovery.

# 找到節點後，使用TCP 7680進行檔案傳輸(P2P)
After discovering peers, TCP port 7680 is used for file transfer(P2P).

# mDNS使用Multicast群組(ipv4)224.0.0.251 / (ipv6)ff02::fb
mDNS uses the multicast groups 224.0.0.251 and ff02::fb for peer discovery.

Situation

# 大量mDNS流量造成Router CPU過載
Excessive mDNS traffic caused high CPU utilization on the router.

Solution

[1]
# 關閉傳遞最佳化
Search "Delivery Optimization" > Disable

[2]
# 關閉REG的mDNS
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\DNSClient 
> mDNSEnabled 
> 0

[3]
# 使用防火牆禁用mDNS Port
Search "Firewall" > Add Outbound Rule > Protocol(UDP) Port(5353) > Block