Default Networks display in routing tables

Any Experts to explain the meaning of Default Networks in the routing tables below:

I see "*"  next to C* and D*
what does that mean ?

Thank you

R2#sh ip route connected 
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, + - replicated route

Gateway of last resort is not set

      192.168.12.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.12.0/24 is directly connected, FastEthernet1/0
L        192.168.12.2/32 is directly connected, FastEthernet1/0
 *    192.168.23.0/24 is variably subnetted, 2 subnets, 2 masks
C*       192.168.23.0/24 is directly connected, FastEthernet0/0
L        192.168.23.2/32 is directly connected, FastEthernet0/0
R2#

R1#sh ip route eigrp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, + - replicated route

Gateway of last resort is not set

D*    192.168.23.0/24 [90/30720] via 192.168.12.2, 00:01:47, FastEthernet0/0
R1#

R1#sh run
Building configuration...

Current configuration : 1213 bytes
!
upgrade fpd auto
version 15.0
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
!
!
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
!        
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
redundancy
!
!
ip tcp synwait-time 5
!
!
!
!        
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.12.1 255.255.255.0
 duplex auto
 speed auto
 !
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
 !
!
interface FastEthernet1/0
 no ip address
 shutdown
 duplex auto
 speed auto
 !        
!
interface FastEthernet1/1
 no ip address
 shutdown
 duplex auto
 speed auto
 !
!
!
!
router eigrp 1
 network 192.168.12.0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
!
no cdp log mismatch duplex
!
!
!        
!
!
!
control-plane
 !
!
!
mgcp fax t38 ecm
mgcp behavior g729-variants static-pt
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line vty 0 4
 login
!
end

R1#


R2#sh run
Building configuration...

Current configuration : 1281 bytes
!
upgrade fpd auto
version 15.0
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R2
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
!
!
ip source-route
no ip icmp rate-limit unreachable
ip cef
!
!        
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
!
!
!
!
!
!
!
redundancy
!
!
ip tcp synwait-time 5
!
!
!
!        
!
!
!
!
interface FastEthernet0/0
 ip address 192.168.23.2 255.255.255.0
 duplex auto
 speed auto
 !
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
 !
!
interface FastEthernet1/0
 ip address 192.168.12.2 255.255.255.0
 duplex auto
 speed auto
 !
!        
interface FastEthernet1/1
 no ip address
 shutdown
 duplex auto
 speed auto
 !
!
!
!
router eigrp 1
 network 192.168.12.0
 network 192.168.23.0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
ip default-network 192.168.23.0
!
no cdp log mismatch duplex
!
!        
!
!
!
!
control-plane
 !
!
!
mgcp fax t38 ecm
mgcp behavior g729-variants static-pt
!
!
!
gatekeeper
 shutdown
!
!
line con 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line aux 0
 exec-timeout 0 0
 privilege level 15
 logging synchronous
 stopbits 1
line vty 0 4
 login
!
end

R2#