Million common configuration is here.

1. Cisco Virtual Lab Convenient startup-config

enable
configure terminal
!
no ip domain-lookup
line console 0
 no login
 exec-timeout 0 0
 logging synchronous
 privilege level 15
exit
line vty 0 15
 no login
 privilege level 15
exit
!
hostname R

• R1

configure terminal
!
interface GigabitEthernet 0/1
 ip address 10.1.1.1 255.255.255.0
 no shutdown
interface GigabitEthernet 0/2
 ip address 10.1.2.1 255.255.255.0
 no shutdown
!
router eigrp 1
 network 10.1.1.1 0.0.0.0
 network 10.1.2.1 0.0.0.0
exit
!
end

• R2

configure terminal
!
interface GigabitEthernet 0/1
 ip address 10.1.2.2 255.255.255.0
 no shutdown
interface GigabitEthernet 0/2
 ip address 10.2.3.2 255.255.255.0
 no shutdown
!
router eigrp 1
 network 10.1.2.2 0.0.0.0
 network 10.2.3.2 0.0.0.0
exit
!
end

• R3

configure terminal
!
interface GigabitEthernet 0/1
 ip address 10.2.3.3 255.255.255.0
 no shutdown
interface GigabitEthernet 0/2
 ip address 10.3.4.3 255.255.255.0
 no shutdown
!
router eigrp 1
 network 10.2.3.3 0.0.0.0
 network 10.3.4.3 0.0.0.0
exit
!
end

• R4

configure terminal
!
interface GigabitEthernet 0/1
 ip address 10.3.4.4 255.255.255.0
 no shutdown
interface GigabitEthernet 0/2
 ip address 10.4.4.4 255.255.255.0
 no shutdown
!
router eigrp 1
 network 10.3.4.4 0.0.0.0
 network 10.4.4.4 0.0.0.0
exit
!
end