12-12-2008 12:54 AM - edited 03-06-2019 02:56 AM
Is it possible to configure eigrp neighbor list with neighbor's loopback interface?
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12-12-2008 02:48 AM
Hello Fuad,
the answer is no because to build EIGRP adjacency you need to use physical interfaces to communicate with somebody else and the two devices have to share a common IP subnet.
on a multilayer switch you could use an SVI ip address as neighbor but there is a L2 link between the two devices
even if you use overlapping ip addresses
r1
int loop1
ip address 10.10.1.1 255.255.255.0
r2
int loop 2
ip address 10.10.1.2 255.255.255.0
the two ip addresses cannot communicate for each router other router's ip address is out its loopback and this defeats a successful communication between them.
if you use /32 ip addresses then the hellos should go trough another L3 link but:
they have TTL 1
The only exception is if there is a physical link and the interface has ip unnumbered loop1 this could be used
Hope to help
Giuseppe
12-12-2008 02:48 AM
Hello Fuad,
the answer is no because to build EIGRP adjacency you need to use physical interfaces to communicate with somebody else and the two devices have to share a common IP subnet.
on a multilayer switch you could use an SVI ip address as neighbor but there is a L2 link between the two devices
even if you use overlapping ip addresses
r1
int loop1
ip address 10.10.1.1 255.255.255.0
r2
int loop 2
ip address 10.10.1.2 255.255.255.0
the two ip addresses cannot communicate for each router other router's ip address is out its loopback and this defeats a successful communication between them.
if you use /32 ip addresses then the hellos should go trough another L3 link but:
they have TTL 1
The only exception is if there is a physical link and the interface has ip unnumbered loop1 this could be used
Hope to help
Giuseppe
12-12-2008 03:03 AM
Thank you!
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