I have been unable to get SNTP and access to the web interface working properly on a Dell PowerConnect 3548p.
In the logs, this message appears over and over again:
04-Jan-2000 20:19:29 :%MNGINF-W-ACL: Management ACL drop packet received on interface Vlan 172 from 172.17.0.3 to 172.18.0.10 protocol 17 service Snmp
172 is the management vlan.
172.17.0.3 is the DNS server 172.18.0.10 is the switch's IP address.
The DNS server and the switch are located on different subnets and separated by routers.
I am unable to access the web interface of the switch from the 172.17.x.x subnet.
I can only access the web interface of the switch if I am accessing it from the 172.18.x.x subnet.
There is also a managed linksys switch on the 172.18.x.x subnet on the 172 vlan, which has no problem with SNTP. I can also access it from the 172.17.x.x network. So, it stands to reason that this is not a firewall or routing issue, but with the 3548p switch.
I suspect the issue is with management permissions/ACLs on the 3548p switch, but that's about as much as I've been able to determine so far.