Hi Everyone,
I recently set up a lab in GNS3 to simulate the EIGRP routing protocol, connecting two ISPs across two sites.
However, I’m encountering a loopback issue based on the trace outputs (the Config files in attachments).
I would appreciate it if anyone could help identify what configuration might be missing or incorrect that’s causing this loopback issue.
Thank you in advance for your support!
========================================
Core-A Trace:
Core-A#traceroute 172.16.4.1 so lo 4
Type escape sequence to abort.
Tracing the route to 172.16.4.1
VRF info: (vrf in name/id, vrf out name/id)
1 10.40.40.1 60 msec
10.40.40.2 60 msec
10.40.40.1 44 msec
2 10.222.0.2 80 msec
10.111.0.2 60 msec
10.222.0.2 92 msec
3 172.18.0.3 136 msec 132 msec 140 msec
Core-A#
=================================================
Core-B Trace:
Core-B#traceroute 10.66.1.1 so lo 1
Type escape sequence to abort.
Tracing the route to 10.66.1.1
VRF info: (vrf in name/id, vrf out name/id)
1 172.18.0.1 72 msec
172.18.0.2 60 msec
172.18.0.1 68 msec
2 10.222.0.1 84 msec
10.111.0.1 84 msec
10.222.0.1 128 msec
3 10.40.40.3 100 msec 88 msec 140 msec
Core-B#
====================================================
====================================================
Core-A
router eigrp 10
network 10.66.4.0 0.0.0.255
network 10.66.3.0 0.0.0.255
network 10.66.2.0 0.0.0.255
network 10.66.1.0 0.0.0.255
network 10.40.40.0 0.0.0.7
----------------------------------
ISP-1-A:
router eigrp 10
address-family ipv4 vrf vpn
autonomous-system 10
network 10.40.40.0 0.0.0.7
network 10.111.0.0 0.0.0.3
--------------------------------
ISP-2-A:
router eigrp 10
address-family ipv4 vrf vpn
autonomous-system 10
network 10.40.40.0 0.0.0.7
network 10.222.0.0 0.0.0.3
++++++++++++++++++++++++++++++++++++
Core-B:
router eigrp 10
network 172.16.4.0 0.0.0.255
network 172.16.3.0 0.0.0.255
network 172.16.2.0 0.0.0.255
network 172.16.1.0 0.0.0.255
network 172.18.0.0 0.0.0.7
--------------------------------
ISP-1-B:
router eigrp 10
address-family ipv4 vrf vpn
autonomous-system 10
network 172.18.0.0 0.0.0.7
network 10.111.0.0 0.0.0.3
----------------------------------
ISP-2-B:
router eigrp 10
address-family ipv4 vrf vpn
autonomous-system 10
network 172.18.0.0 0.0.0.7
network 10.222.0.0 0.0.0.3
The loopback issue has been resolved after creating a PC node instead of the loopback interface.
I believe this might be related to the GNS3 application’s handling of loopback interfaces, As @paul driver mentioned in his previous comment "each core loopback is calculated the same."
Thank you, @Flavio Miranda @paul driver @MHM Cisco World for your continued support. I truly appreciate it!
