I'm trying to set up a DMVPN Phase 2 configuration, but I cannot manage to get past Phase 1 because the hub router's tunnel interface refuses to disable split-horizon. The spokes never form an EIGRP adjacency to teach other and never learn routes directly to the other spokes.
I'm looking for suggestions on something I may be doing wrong. I've tried disabling on the interface itself and in the routing configuration as well just be sure. When I check the interface, it still says split horizon is enabled.
I haven't added any optimizations commands yet or anything unnecessary to establish communication. Once I can get my spokes talking directly, I'll worry about improving the configuration. This is solely a test environment right now.
EDIT: To clarify, the fact that spokes receive no routes to other spokes and never form adjacencies tells me that split horizon is still on. The Tun1601 interface shows split horizon still enabled. Sh ip eigrp interface says thats its disabled. Short of taking a packet capture and investigating what's really happen, it seems it is in fact not disabled.
interface Tunnel1601 description DMVPN over INTERNET bandwidth 1000 ip vrf forwarding Green ip address 172.17.13.7 255.255.252.0 no ip redirects ip mtu 1400 no ip split-horizon eigrp 1601 ip nhrp authentication NHRPKey2 ip nhrp map multicast dynamic ip nhrp network-id 1601 ip nhrp holdtime 300 ip nhrp registration timeout 30 tunnel source Port-channel2.7 tunnel mode gre multipoint tunnel key 100001 tunnel vrf INTERNET tunnel protection ipsec profile IPSEC-INTERNET router eigrp DMVPN-INTERNET ! address-family ipv4 unicast vrf Green autonomous-system 1601 ! af-interface Tunnel1601 no next-hop-self no-ecmp-mode no split-horizon exit-af-interface ! topology base exit-af-topology network 172.17.12.0 0.0.3.255 network 172.30.3.0 0.0.0.255 network 172.30.6.0 0.0.0.255 exit-address-family
Sh ip int tun1601:
Tunnel1601 is up, line protocol is up Internet address is 172.17.13.7/22 Broadcast address is 255.255.255.255 Address determined by setup command MTU is 1400 bytes Helper address is not set Directed broadcast forwarding is disabled Multicast reserved groups joined: 18.104.22.168 22.214.171.124 Outgoing access list is not set Inbound access list is not set Proxy ARP is enabled Local Proxy ARP is disabled Security level is default Split horizon is enabled ICMP redirects are never sent ICMP unreachables are always sent ICMP mask replies are never sent IP fast switching is enabled IP Flow switching is disabled IP CEF switching is enabled IP CEF switching turbo vector IP Null turbo vector VPN Routing/Forwarding "Green" Associated unicast routing topologies: Topology "base", operation state is UP Tunnel VPN Routing/Forwarding "INTERNET" IP multicast fast switching is enabled IP multicast distributed fast switching is disabled IP route-cache flags are Fast, CEF Router Discovery is disabled IP output packet accounting is disabled IP access violation accounting is disabled TCP/IP header compression is disabled RTP/IP header compression is disabled Probe proxy name replies are disabled Policy routing is disabled Network address translation is disabled BGP Policy Mapping is disabled Input features: MCI Check, TCP Adjust MSS Output features: TCP Adjust MSS Post encapsulation features: IPSEC Post-encap output classification IPv4 WCCP Redirect outbound is disabled IPv4 WCCP Redirect inbound is disabled IPv4 WCCP Redirect exclude is disabled
sh ip eigrp vrf Green int
EIGRP-IPv4 VR(DMVPN-INTERNET) Address-Family Interfaces for AS(1601) VRF(Green) Xmit Queue PeerQ Mean Pacing Time Multicast Pending Interface Peers Un/Reliable Un/Reliable SRTT Un/Reliable Flow Timer Routes Tu1601 1 0/0 0/0 62 0/22 252 0 Lo2 0 0/0 0/0 0 0/0 0 0 Gi0/1 0 0/0 0/0 0 0/0 0 0