Effect of autosummary

Router6 will not add 10.0.0.0/8 network, because it already has 10.10.10.1/30 on its fast ethernet. Same for all routers.

Check the debug command
*Mar  1 00:14:17.495: IP-EIGRP(Default-IP-Routing-Table:1): route installed for 20.0.0.0  (Summary)
*Mar  1 00:14:17.559: IP-EIGRP(Default-IP-Routing-Table:1): 10.10.10.1/32 – don’t advertise out Serial0/1
*Mar  1 00:14:17.559: IP-EIGRP(Default-IP-Routing-Table:1): 10.10.10.2/32 – don’t advertise out Serial0/1
*Mar  1 00:14:17.559: IP-EIGRP(Default-IP-Routing-Table:1): 10.10.10.3/32 – don’t advertise out Serial0/1
*Mar  1 00:14:17.559: IP-EIGRP(Default-IP-Routing-Table:1): 20.0.0.0/8 - poison advertise out Serial0/1
*Mar  1 00:14:17.559: IP-EIGRP(Default-IP-Routing-Table:1): Int 20.0.0.0/8 metric 2169856 – 1657856 512000
*Mar  1 00:14:17.599: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.0.0.0/8 metric 2172416 – 1657856 514560
*Mar  1 00:14:17.671: IP-EIGRP(Default-IP-Routing-Table:1): Processing incoming REPLY packet
*Mar  1 00:14:17.671: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.0.0.0/8 M 2172416 – 1657856 514560 SM 28160 – 25600 2560
*Mar  1 00:14:17.671: IP-EIGRP(Defa
R4(config-routult-IP-Routing-Table:1): route installed for 10.0.0.0  ()
*Mar  1 00:14:17.671: IP-EIGRP(Default-IP-Routing-Table:1): route installed for 10.0.0.0  (Summary)
*Mar  1 00:14:17.687: IP-EIGRP(Default-IP-Routing-Table:1): 10.0.0.0/8 – do advertise out Serial0/1
*Mar  1 00:14:17.687: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.0.0.0/8 metric 128256 – 256 128000er)#
R4(config-router)#
*Mar  1 00:49:56.087: IP-EIGRP(Default-IP-Routing-Table:1): Processing incoming QUERY packet
*Mar  1 00:49:56.091: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.20.20.2/32 M 4294967295 – 25600 4294967295 SM 4294967295 – 25600 4294967295
*Mar  1 00:49:56.091: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.20.20.3/32 M 4294967295 – 25600 4294967295 SM 4294967295 – 25600 4294967295
*Mar  1 00:49:56.111: IP-EIGRP(Default-IP-Routing-Table:1): 10.20.20.2/32 – not in IP routing table
*Mar  1 00:49:56.111: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.20.20.2/32 metric 4294967295 – 0 4294967295
*Mar  1 00:49:56.111: IP-EIGRP(Default-IP-Routing-Table:1): 10.20.20.3/32
R4(config-router)#- not in IP routing table
*Mar  1 00:49:56.115: IP-EIGRP(Default-IP-Routing-Table:1): Int 10.20.20.3/32 metric 4294967295 – 0 4294967295