Understanding Passive interface in EIGRP

by  the way , Passive interface in EIGRP blocks the incoming and outgoing advertisement.
What I have concluded from reading on the Net, is some routers version will advertize EIGRP with the classfull IP adress by default when you redistribute them into other other Routing Protocols such as OSPF. so the work around is to block the advertizement manually by making the interfaces that connect the ABR to the OSPF as Passive, then for instance, create Access-List that encompass the classless subnets of the EIGRP and Tag them, so that later when you redistribute the EIGRP routes you can use the Route Map to mach the Tag.

*** I might be going too far, but I wanted to make sure that Passive interface will come handy in the case where the router version will advertise the classful network ie, 172.16.10.0 as 172.16.0.0 even when you specify the wild card mask of 0.0.0.255.

thpipfh: I have been to that link before I posted the Question. Thank you though.

What I need to know, in case you want to redistribute Classles IP address of a subnet from EIGRP AS to OSPF when the router version(in the EIGRP AS) does allow only the classful subnet.

because in some version if you type for example : Network 10.24.24.0 ?
the help does not show the wild card mask to enter.
what s the work around ?

Please give me what model device you are using ??

what is the ios vertion ?

If you have seen CBT Nuggets CCIE videos Advanced OSPF configuration. the instructor, had to use the passive interfaces to prevent the router from advertizing EIGRP domain routes, because the ASBR allow only classful IP addresses from EIGRP
So he used passive interfaces, then as a work around he used access-list that permits the /24 subnets mixing it up with Tags and Route maps.. it is not really clear to me...but that would be helpful if any Cisco expert out there can elaborate on that with an example

Thank you