Thanks a lot for all answers.

There are at least two reason that I know of that it makes sense to use static over dynamic. First being that in many cases software based iscsi targets often listen on multiple IPs by default, if the sever is multi-homed. You don't want iscsi intiator to obtain IPs of a target for which intiator has no way of reaching.

First: Do I understand it correct that the Dynamic Discovery does not ask for which LUNs that are present? (That was what I thought). And that it asks a certain IP address at a certain TCP port for which "targets" it has? And that the returned list could be a list of IP addresses if the iSCSI server has several?

Second: Why is it software based iSCSI targets (that would something running on a OS and not on a "real" SAN then?) more often has several IP addresses? Could not a SAN based iSCSI target have several IP addresses, perhaps to be able to spread the sessions over aggregated links (802.3ad) on switches and up to the ESX with "ip hash" load balancing?