A niche post as it will only directly impact HiNet customers and any system relaying outbound mail via msr.hinet.net that is not already using SMTP AUTH over TLS on port 587. However it may be indicative of a shift in attitudes towards email from even smaller players in Asia and security of the channel.
Chunghwa Telecom (HiNet) will enforce SMTP AUTH with TLS for all outbound submissions starting Q4 2025. Client mail must submit to msr.hinet.net on port 587 using TLS/STARTTLS with account/password authentication.
Scope
- Change applies to message submission (MSA). No inbound MX or server‑to‑server policy change is announced.
Required settings
- SMTP server:
msr.hinet.net - Port: 587
- Security: TLS or STARTTLS
- Auth: Required (username/password)
Operational impact
- TW users, MFPs, CRMs, and legacy MUAs on port 25 or without AUTH must be reconfigured or outbound mail will fail post‑cutover. Expect transient sending issues from TW‑based users who do not update in time. (Inference from submission change.)
- Port 587 is the recommended submission port for authenticated, encrypted client traffic.
Actions for providers
- Audit TW customer configs now. Migrate all client submissions to 587 with AUTH+TLS. Publish vendor‑specific steps and preempt support tickets.
Source: HiNet notice- Hinet Webmail
