Hi,
My lab is configured like this.
R1(s1)----(s1)R2(s2)-----(s2)R3
R1 and R2 are connected via serial1 interfaces and R2 and R3 are connected via serial2 interfaces.
I am confused with 'ip default-network' command. I read a few notes about it and what they explain and what I see when I test it in a lab; has got some differences.
Almost all the notes that I read say;
If I give 'ip default-network 1.1.1.0' command in R2 (because I can reach 1.1.1.0/24 network from R2) I should see a gateway of last resort in R3.
But the reality is a little different from this.
What actually happens is, this doesn't happen when I have given 'no auto-summary' command given in R1 and R2. But if I again say, 'auto-summary' in R1 and R2, then in R3 I see the gateway of last resort set to R2.
My second doubt is, when I give the command 'show ip protocol' in R1 and R2, I see something called, "(this router)" under Gateway. The outputs of show run, show ip route, show ip protocol commands are posted below.
Can someone please clarify this to me?
Thanks in advance!
R1#sh run
Building configuration...
Current configuration : 1115 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname R1
!
!
!
!
!
!
ip subnet-zero
!
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
!
interface Ethernet0
description First ethernet interface connects to wg_sw_a
no ip address
shutdown
!
interface Serial0
description First serial interface is configured as a DTE interface
bandwidth 64
no ip address
shutdown
no fair-queue
!
interface Serial1
bandwidth 64
ip address 10.10.10.1 255.255.255.0
!
router eigrp 100
network 1.0.0.0
network 10.0.0.0
auto-summary
no eigrp log-neighbor-changes
!
ip classless
ip default-network 1.0.0.0
ip http server
!
end
R1#sh ip route
Gateway of last resort is 0.0.0.0 to network 1.0.0.0
* 1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D* 1.0.0.0/8 is a summary, 01:09:23, Null0
C 1.1.1.0/24 is directly connected, Loopback0
D 2.0.0.0/8 [90/40640000] via 10.10.10.2, 01:09:04, Serial1
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/41152000] via 10.10.10.2, 01:09:03, Serial1
D 20.0.0.0/8 [90/41024000] via 10.10.10.2, 01:09:04, Serial1
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 10.0.0.0/8 is a summary, 01:09:24, Null0
C 10.10.10.0/24 is directly connected, Serial1
R1#sh ip protocol
Routing Protocol is "eigrp 100"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Default networks flagged in outgoing updates
Default networks accepted from incoming updates
EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
EIGRP maximum hopcount 100
EIGRP maximum metric variance 1
Redistributing: eigrp 100
Automatic network summarization is in effect
Automatic address summarization:
10.0.0.0/8 for Loopback0
Summarizing with metric 40512000
1.0.0.0/8 for Serial1
Summarizing with metric 128256
Maximum path: 4
Routing for Networks:
1.0.0.0
10.0.0.0
Routing Information Sources:
Gateway Distance Last Update
(this router) 90 01:10:04
10.10.10.2 90 01:09:44
Distance: internal 90 external 170
