https://community.ee.co.uk/t5/Mobile-Broadband/UDP-Port-123-Restriction-on-Mobile-Broadband-SIM/m-p/1632180#M35179 <P>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.</P><P>Details:<BR />- SIM Network Type: LTE PLUS<BR />- 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<BR />- General internet connectivity (web browsing, data usage) works fine on this SIM<BR />- I suspect NTP traffic (UDP port 123) may be blocked or restricted on this SIM/connection</P><P>Can I check if the UDP port 123 is blocked or restricted without asking EE directly?</P> Sat, 01 Aug 2026 14:21:10 GMT cesca3 2026-08-01T14:21:10Z https://community.ee.co.uk/t5/Mobile-Broadband/UDP-Port-123-Restriction-on-Mobile-Broadband-SIM/m-p/1632180#M35179 <P>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.</P><P>Details:<BR />- SIM Network Type: LTE PLUS<BR />- 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<BR />- General internet connectivity (web browsing, data usage) works fine on this SIM<BR />- I suspect NTP traffic (UDP port 123) may be blocked or restricted on this SIM/connection</P><P>Can I check if the UDP port 123 is blocked or restricted without asking EE directly?</P> Sat, 01 Aug 2026 14:21:10 GMT https://community.ee.co.uk/t5/Mobile-Broadband/UDP-Port-123-Restriction-on-Mobile-Broadband-SIM/m-p/1632180#M35179 cesca3 2026-08-01T14:21:10Z https://community.ee.co.uk/t5/Mobile-Broadband/UDP-Port-123-Restriction-on-Mobile-Broadband-SIM/m-p/1632189#M35183 <P>No ports are blocked other than unauthenticated SMTP (25) to prevent spam originating from EE. See&nbsp;</P><DIV class=""><A href="https://ee.co.uk/content/dam/help/terms-and-conditions/broadband/network-traffic-management/ee-mobile-broadband-traffic-management.pdf" target="_blank" rel="noopener">EE Mobile Broadband Traffic Management Policy T&amp;Cs</A></DIV> Sat, 01 Aug 2026 14:50:39 GMT https://community.ee.co.uk/t5/Mobile-Broadband/UDP-Port-123-Restriction-on-Mobile-Broadband-SIM/m-p/1632189#M35183 XRaySpeX 2026-08-01T14:50:39Z