Each network has their own Services, some have none, some have more widely used Services packages such as Epona, but DALnet has its own - they have nothing to do with mIRC.
When a channel is registered on DALnet, although a person will be opped when they join your channel (when it's empty), ChanServ will automatically deop them. This can be changed with the LEAVEOPS option, see
/chanserv help set leaveops.
To set a topic, use
/topic #channel new-topic-here. When you leave the channel empty and come back, by default, the channel topic will be gone. You need to set the KEEPTOPIC option on so that ChanServ saves it - use
/chanserv set #channel keeptopic on. There are not greet message options on DALnet, although the topic greets people when they join.
For further help with DALnet services, the best place to go is #Help or #DALnetHelp or DALnet. Also see
http://docs.dal.net and type
/services help when connected to DALnet.
Regards,