UDP Port 123) Restriction on Mobile Broadband SIM

cesca3 · ‎01-08-2026

I'm using an EE SIM in a mobile broadband router (TP-Link Archer MR505) and I'm having trouble with the router's NTP time sync, which in turn seems to be causing a knock-on issue with the router's cloud/remote management features failing.

Details:
- SIM Network Type: LTE PLUS
- The router is unable to sync time via NTP (tried multiple NTP servers: time.google.com, pool.ntp.org, time.windows.com) and receives a consistent timeout when attempting to reach any of them
- General internet connectivity (web browsing, data usage) works fine on this SIM
- I suspect NTP traffic (UDP port 123) may be blocked or restricted on this SIM/connection

Can I check if the UDP port 123 is blocked or restricted without asking EE directly?

XRaySpeX · ‎01-08-2026

No ports are blocked other than unauthenticated SMTP (25) to prevent spam originating from EE. See

EE Mobile Broadband Traffic Management Policy T&Cs

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To phone EE CS: Dial Freephone +44 800 079 8586 - Option 1 for Home Broadband & Home Phone or Option 2 for Mobile Phone & Mobile Broadband

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