U.u.u. ????????????

Cheers all hope all is well, can some one assist me on the concepts of the U.U.U's ... Did the packets get to it's destination or floating in limbo???

I have two AS's 6500 5500 running BGP, the 5500 as has 4 routers all running ospf for internal routing, two transit router only running ospf and two bgp routers running ibgp. They are peered with one another using loopback IP addresses, the 6500ASas has 1 router only running bgp and is peered with one of the 5500 bgp routers r4.... the external AS 6500 is advertising multiple networks in AS5500 routers say r1 & r4 . R1 & R4 are in the same as5500 running ibgp (not meshed, not directly connected using loop backs as neighbors but is exchanging routes) transiting through two routers only running ospf.

r4 router is peered up with (as6500 router r5) and the r4 router has all the advertised r5 routes........... all is well. (working)

I have another bgp router running on the other end of the AS5500 named r1 with a lot of networks connected running OSPF internally

the two BGP routers in the AS5500 are IBGP peers. The (as6500) routes are in the bgp table and the routing table of r1, however, when im on r1 trying to ping them external bgp routes AS6500 that i see in my routing table as valid im getting
u.u.u

SIGH.............

Success rate is 0 percent (0/5)

can anyone help

thanks

Find more posts tagged with

Free for TechExams community: Cybersecurity salary guide

Compare cert salaries and plan your next career move

Button

Comments

SteveO86

Your getting ICMP unreachables back, should be a routing issue somewhere. Might want to post the configs.

I believe unreachables are rate-limited by default which is why you get one unreachable, one timeout (rinse and repeat) leading the U.U.U pattern

networker050184

I believe you are running into a very common mistake for beginner BGPers. A couple things to look at.

Next hop reachable?
Is the source of the pings reachable?

Tommy2727

Yes next hop is reachable, the puzzling thing is I'm seeing the routes in my routing table... If any confg was wrong in the AS's i wouldn't see the routes in the routing table...

Tommy2727

Router#sh ip bgp
BGP table version is 9, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 0.0.0.0 0 32768 i
*>i50.1.1.0/24 4.4.4.4 0 100 0 6500 i
*>i200.1.1.0 4.4.4.4 0 100 0 6500 i
*>i200.1.2.0 4.4.4.4 0 100 0 6500 i
*>i200.1.3.0 4.4.4.4 0 100 0 6500 i
*>i200.1.4.0 4.4.4.4 0 100 0 6500 i
*>i200.1.5.0 4.4.4.4 0 100 0 6500 i
*>i200.1.6.0 4.4.4.4 0 100 0 6500 i
Router#sh ip rou
Router#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

B 200.1.4.0/24 [200/0] via 4.4.4.4, 03:20:31
1.0.0.0/32 is subnetted, 1 subnets
C 1.1.1.1 is directly connected, Loopback1
50.0.0.0/24 is subnetted, 1 subnets
B 50.1.1.0 [200/0] via 4.4.4.4, 03:20:31
B 200.1.5.0/24 [200/0] via 4.4.4.4, 03:20:31
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback2
B 200.1.6.0/24 [200/0] via 4.4.4.4, 03:20:31
4.0.0.0/32 is subnetted, 1 subnets
O 4.4.4.4 [110/129] via 10.1.13.2, 03:50:14, Serial0/0
[110/129] via 10.1.12.2, 03:50:15, Serial0/1
B 200.1.1.0/24 [200/0] via 4.4.4.4, 03:20:33
B 200.1.2.0/24 [200/0] via 4.4.4.4, 03:20:34
B 200.1.3.0/24 [200/0] via 4.4.4.4, 03:20:34
10.0.0.0/24 is subnetted, 4 subnets
C 10.1.13.0 is directly connected, Serial0/0
C 10.1.12.0 is directly connected, Serial0/1
O 10.1.24.0 [110/128] via 10.1.12.2, 03:50:16, Serial0/1
O 10.1.34.0 [110/128] via 10.1.13.2, 03:50:16, Serial0/0
Router#ping 200.1.2.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.1.2.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)
Router#ping 200.1.3.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 200.1.3.1, timeout is 2 seconds:
U.U.U
Success rate is 0 percent (0/5)

SteveO86

Does the other side have a route back?

Tommy2727

SteveO86 wrote: »

Does the other side have a route back?

No I was thinking the same ,,, should I add a default or static route all the way through to that side, then again the routes are in the table on the that side, is it the way Im advertising these routes, im using the network command..

R5#sh ip bgp
BGP table version is 21, local router ID is 200.1.6.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*> 2.2.2.0/24 10.1.45.1 0 5500 i
*> 50.1.1.0/24 0.0.0.0 0 32768 i
*> 200.1.1.0 0.0.0.0 0 32768 i
*> 200.1.2.0 0.0.0.0 0 32768 i
*> 200.1.3.0 0.0.0.0 0 32768 i
*> 200.1.4.0 0.0.0.0 0 32768 i
*> 200.1.5.0 0.0.0.0 0 32768 i
*> 200.1.6.0 0.0.0.0 0 32768 i
R5#sh ip rou
R5#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

C 200.1.4.0/24 is directly connected, Loopback3
50.0.0.0/24 is subnetted, 1 subnets
C 50.1.1.0 is directly connected, Loopback6
C 200.1.5.0/24 is directly connected, Loopback4
2.0.0.0/24 is subnetted, 1 subnets
B 2.2.2.0 [20/0] via 10.1.45.1, 04:39:16
C 200.1.6.0/24 is directly connected, Loopback5
C 200.1.1.0/24 is directly connected, Loopback0
C 200.1.2.0/24 is directly connected, Loopback1
C 200.1.3.0/24 is directly connected, Loopback2
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.45.0 is directly connected, Serial0/0
R5#ping 2.2.2.2

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

inscom.brigade

Networker050184 is this limited to BGP, or could it also be associated to distance vector?

I saw this last evening when I did a ping. u.u.u.u.u.
I thought I was just tired and dropped my forhead to the desk. I am not running BGP, but have ripv2 running.

networker050184

The issue is simple routing, but it's something a lot of people seem to miss with BGP due to the lack of end to end IGP connectivity.