Topology_OSPF_Stubs

So I actually did not wr mem any routers from my previous lab where Area 15 and 34 were turned into virtual-links, so we are back to the NSSA for Area 15 and the Total Stub on Area 34. My goal is to figure out if and where static IP’s can be assigned to route traffic between Total Stub networks, and possibly get into Authentication and how it affects connectivity if time permits as I am fried already from work so going right back to the CLI is like pulling teeth some days 🙂 So the same old topology is shown that I will be working with.

So without reading the old post, I remember from R5 I could ping all the way to R4’s 172.12.34.4 FastEthernet interface, but couldn’t reach it’s loopback of 4.4.4.4 and vice versa to R5’s loopback of 5.5.5.5. So R1 and R3 are not learning these OSPF routes due to lack of a Virtual-Link, so I am thinking either a static route on each or a static route redistributed into OSPF (so this could get messy). Lets start on R1:

R1#ping 5.5.5.5

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)
R1#conf t
R1(config)#ip route 5.5.5.5 255.255.255.255 fa0/1
R1(config)#do ping 5.5.5.5

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/2/4 ms
R1(config)#

Easy as that, jump to R3 to create a static route to 4.4.4.4 and ping 5.5.5.5 from R4:

R4#ping 5.5.5.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
R4#

Where is my rage face emoji. There has to be a logical solution, and I think it is a static route needs to actually be added on those Non-Backbone routers as well, but I am going to confirm how far I can ping and not drop packets:
R4#ping 172.12.15.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.12.15.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 64/65/68 ms
R4#

Same thing as before, the return route needs to also be placed on the Stub routers to make this work I am hoping, that way I can say I learned something and get into Area Authentication. So I will just mirror the ip route statements on their stub routers:

R5(config)#ip route 4.4.4.4 255.255.255.255 fa0/1
R5(config)#do ping 4.4.4.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)
R5(config)#

So we have gone from U.U.U to complete packet loss, however I can still hit R4’s Fa0/1 IP:

R5#ping 172.12.34.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 172.12.34.4, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 64/65/68 ms
R5#ping 4.4.4.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)
R5#

So something has got to give here, we went from an upstream router not knowing where to send traffic, to R4 and R5 dropping the others packets to the loopbacks. I first remove the static routes from R4 and R5 and ping again to confirm I am back to U.U.U, however I am going to get on the ASBR R1 and see if I can redistribute my was to routing success:

R1(config)#ip route 4.4.4.4 255.255.255.255 172.12.123.3
R1(config)#no ip route 5.5.5.5 255.255.255.255 fa0/1
R1(config)#ip route 5.5.5.5 255.255.255.255 172.12.15.5
R1(config)#router ospf 1
R1(config-router)#redistribute static subnets metric-type 1
R1(config-router)#

So as can be seen, to keep things consistent I changed the static route from an interface to the remote routers IP address, as I can’t send 4.4.4.4 traffic out the Serial interface as I have two spoke routers off of it and only one of them contains 4.4.4.4. Though it would be interesting to see if it would be 50% loss rate of packets or if they would all tank, I’ll try that out once I have this resolved. So here is how things look:

R3#show ip route ospf
     1.0.0.0/32 is subnetted, 1 subnets
O IA    1.1.1.1 [110/65] via 172.12.123.1, 00:33:45, Serial0/2
     2.0.0.0/32 is subnetted, 1 subnets
O IA    2.2.2.2 [110/65] via 172.12.123.2, 00:33:45, Serial0/2
     100.0.0.0/13 is subnetted, 1 subnets
O E1    100.0.0.0 [110/84] via 172.12.123.1, 00:33:45, Serial0/2
     5.0.0.0/32 is subnetted, 1 subnets
O E1    5.5.5.5 [110/85] via 172.12.123.1, 00:07:17, Serial0/2
     172.12.0.0/24 is subnetted, 3 subnets
O IA    172.12.15.0 [110/65] via 172.12.123.1, 00:33:45, Serial0/2
     172.16.0.0/22 is subnetted, 1 subnets
O IA    172.16.8.0 [110/65] via 172.12.123.1, 00:33:45, Serial0/2
R3#

Ok, this HAS GOT TO WORK this time around, and yes I do just generally change the metric type to 1 automatically now with OSPF redistribution as not to get the seed metric of 20. So let the routing gods pass traffic between these two Stub networks so that I may move on:

R4#ping 5.5.5.5
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 5.5.5.5, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 64/65/68 ms
R4#

YESSSSSS!!!!! YES YES YESSSSS!!!!!! TAKE THAT LOGICAL BEHAVIOR!!!

So that is awesome that I stumbled across that, worked through the issue, and learned a great lesson here about mixing static routing with Redistribution for Stub communication. That’s a lot of routing mechanisms working against a packet to get to it’s destination and back, but that packet was sent and returned! Now, I am going to break it again, because I am curious if I used interfaces instead of remote IP’s for the static routes:

R1(config)#no ip route 5.5.5.5 255.255.255.255 172.12.15.5
R1(config)#no ip route 4.4.4.4 255.255.255.255 172.12.123.3
R1(config)#ip route 5.5.5.5 255.255.255.255 fa0/1
R1(config)#ip route 4.4.4.4 255.255.255.255 s0/0

I first want to try pinging from R1 to 4.4.4.4 to see if there is connectivity at all:

R1(config)#do ping 4.4.4.4

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 4.4.4.4, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)
R1(config)#

I do believe if this was an EIGRP topology (which I may check at some point), it would actually equal-cost load balance that traffic so we might see ping results like ..!.! or basically 50% packet loss sending the traffic to both neighbors and only one replying.

HOWEVER, this is not EIGRP, so I will add the static routes by remote IP again, and I am going to be a slacker and call it a night here on the equipment because my belly is grumbling feed me and I feel I have learned a LOT from this lab session.

Next up, Authentication, then Redistribution and I think we are caught up!