Issues facing after upgrading the switch to MS15.21.1

[Anilraj]

We have few devices connected to switch and they are unable to get the DHCP IP address from server after switch upgraded to 15.21.1, before it was worked fine over long period. Those switch ports are included under access policies.

When we test it by rollbacking the version to 14.x, it started working fine. We had done packet captures for both the cases and have seen dhcp replies from server on 14.x whereas there is no replies on 15.21.1. Have taken captures on MX as well but not found any dhcp packets coming from 15.x switch.

[alemabrahao]

Have you opened a support case?

[Anilraj]

Have opened it and currently it's pending with support team.

[PhilipDAth]

Have you got any DHCP server restrictions configured under "Switches/DHCP servers & ARP"?

Does that page show any blocked DHCP servers?

[Anilraj]

Not having any such restrictions, got update from support team that there is some changes between versions on VLAN assignments and looks it is working fine after making the suggested changes.

Thank you.

[RaphaelL]

Are you using group policies by any chances ?

Some trafic ( like DNS and DHCP ) were implicitly allowed before MS15. It has changed , no idea if intended or not.

[Anilraj]

Yep, we are using group policies and similar update we received from support team and suggested some changes on ports. Everything looking good now after this update.Thank you😊

[JacekJ]

Hi, can you share what the suggestions were?