I found same question from below link.
Basically I like to inject default route through EIGRP at R3 and R4.
R3 R1 R7 are loated in Data center and R4 R9 R8 are loated in HQ.
So when internet line is down at each site, I like to inject default route through R7 - R8 (MPLS).
I used "distance 200 source ip mask ACL" to adjust default route with interface summary command.
But, production line, we have ASA instead of R3 that it only injected "EX D with 0.0.0.0"
Problem is that this "EX D" can't be adjusted AD value, it is always "170"
router eigrp 1
distance 171 220.127.116.11 0.0.0.0 1
access-list 1 0.0.0.0
----> it doesn't change AD value as 171 when redistribution occured on R4 "D EX"
However if I injucted default route on R4 through interface "D"
int f0/0 (facing R9)
ip summary -address eigrp 1 0.0.0.0 0.0.0.0
then it will inject "E 0.0.0.0" not "DX E 0.0.0.0" in this case, I can change AD value through "distance 171 18.104.22.168 0.0.0.0 1"
Is there any way that I can adjust AD value between R7 and R8 while default route is "D EX"? so that default route is used for each site unless internet line is down for each site.