Azure File Storage uses SMB 3.0's encrypted transport to enable access via the Internet.

This often requires organizations to unblock port 445 for outbound TCP traffic.

For many small businesses and residential homes, ISP's may block 445.

We have put together this Wiki page for people to add their ISP's based on their experiences. Please update the Wiki page with relation to whether your ISP allows or disallows use of SMB3 and a link to the ISP's policy.

Table of Contents



  • Frontier - Allowed, however their website appears to indicate it is blocked - potentially this is just for inbound traffic.
  • AT&T - Through a cellphone wifi hotspot.
  • Mediacom - Allowed
  • CenturyLink - Allowed
  • KPN - Allowed (Completely unblocked since 2017)
  • Time Warner Cable - Allowed
  • Paxio (Silicon Valley) - Allowed
  • DST (Brunei) -  Allowed
  • TelBru (Brunei) - Fiber Optic  Allowed
  • Entel Peru - Internet Mobile
  • Vivo Fibra (Brazil) - Home and Business users 
  • Verizon - Home and Business



  • AT&T U-Verse
  • Charter Spectrum 
  • Charter Spectrum Business
  • Comcast - See
  • Cox Communication -Residential See: Cox Internet Ports Blocked
  • Verizon Wireless - Through a cellphone wifi hotspot.
  • T-Mobile - Through a cellphone WiFi hotspot.
  • Optimum Online - port 445 is disallowed for both residential and business accounts
  • Ziggo
  • Telenet
  • OnsBrabantNet Glasvezel
  • XS4All
  • Videotron
  • RCN
  • Rogers Cable (Canada) - All Home and SMB Services (including Ignite)
  • Movistar Peru- All Home Service
  • Claro Peru- All Home Service
  • NET Virtua (Brazil)
  • Vivo Mobile (Brazil) - 4G, LTE and 3G
  • Vodafone (India) - 4G, LTE and 3G


See also