/32 routes received from ospf doesnt works

Created: Oct 17, 2019 06:16:40Latest reply: Oct 22, 2019 08:02:42 352 7 0 0
  Hi-coins as reward: 0 (problem unresolved)

Hi,

I have 6720S-EI its doing ospf with other routers. The routes received are /32 but sometimes they work sometimes they dont work. I can see them in the routing table but there access to the internet cloud is not working. example
10.10.10.0/24  NULL0

received routes with 10.10.10.1/32 etc from ospf neighbours. The problem is sometimes these routes work sometimes they dont but they are in routing table. Adding a static route of 10.10.10.1/32 and that ip will start working. Remove the static route and use ospf received route it will keep on working but till when dont know.

I can ping from 6720 to ospf peers and their IPs advertised but from internet i cannot. Looks like null route is taking priority. Help or advice would be appreciated.


thanks




network

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Featured Answers
Popeye_Wang
Admin Created Oct 22, 2019 08:02:42 Helpful(0) Helpful(0)

Posted by hashbang at 2019-10-17 11:08Posted by chenhui at 2019-10-17 11:08@hashbang hello,as you said, when the static route 10.10.10.1/3 ...

Do you mean that the 32-bit routes learned by OSPF on S6720 are advertised to the external network through BGP but cannot be accessed from the external network?
And after the static route to the 32-bit address is added to the S6720, the route is ok?
Am I right? If so, as #7 said, you may need to configure the default route or redistribute.
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All Answers
Popeye_Wang
Popeye_Wang Admin Created Oct 17, 2019 08:08:39 Helpful(0) Helpful(0)

You mean that 10.10.10.0 belongs to these two routers, and this address cannot access the Internet? Can you explain it more clearly?? If you can share the key configuration, it will be helpful.
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hashbang
hashbang Created Oct 17, 2019 08:28:51 Helpful(0) Helpful(0)

Posted by Popeye_Wang at 2019-10-17 08:08 You mean that 10.10.10.0 belongs to these two routers, and this address cannot access the Internet? ...
yes, these routers advertise /32 routes to 6720. /32 route is received but not taking priority over NULL route used for bgp to upstream provide. I hope this explains more clearly
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hashbang
hashbang Created Oct 17, 2019 08:30:22 Helpful(0) Helpful(0)

Posted by hashbang at 2019-10-17 08:28 yes, these routers advertise /32 routes to 6720. /32 route is received but not taking priority ov ...
this setup was working fine on mikrotik till i replaced it with 6720 a year back
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chenhui
chenhui Admin Created Oct 17, 2019 09:40:26 Helpful(0) Helpful(0)

@hashbang hello,
as you said, when the static route 10.10.10.1/32 is added, the router could reach the internet(BGP side), and if the static route is removed, the connection turns down. And I noticed that you said the OSPF route 10.10.10.1/32 does exist in the routing-table no matter the static route 10.10.10.1/32 configured or not.

Based on these information, I'm curiosity about the routing-table items when the static route configured. as you said, there will be two routes towards to the 10.10.10.1/32.

You are kindly advised to upload the corresponding configuration, I'm really confused. :)
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hashbang
hashbang Created Oct 17, 2019 11:08:49 Helpful(0) Helpful(0)

Posted by chenhui at 2019-10-17 09:40@hashbang hello,as you said, when the static route 10.10.10.1/32 is added, the router could reach th ...

ty,
giving you real scenario without using fake ips
this is the route received not static route added just ospf received routes
   x.86.175.9/32  O_ASE   150  20          D   x.208.153.201 Vlanif4000
now i cannot ping this ip from internet
--------------------------------------------------------------------
this is a pppoe user running on bsd pppoe-server (ospf peer)
ng0: flags=88d1<UP,POINTOPOINT,RUNNING,NOARP,SIMPLEX,MULTICAST> metric 0 mtu 1480
        inet x.208.153.201 --> x.86.175.9 netmask 0xffffffff
        inet6 fe80::1859:cd17:e802:b1fe%ng0 prefixlen 64 tentative scopeid 0x7
        nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
i can ping from 6720
PING x.86.175.9: 56  data bytes, press CTRL_C to break
    Reply from x.86.175.9: bytes=56 Sequence=1 ttl=63 time=1 ms
    Reply from x.86.175.9: bytes=56 Sequence=2 ttl=63 time=1 ms
    Reply from x.86.175.9: bytes=56 Sequence=3 ttl=63 time=1 ms
    Reply from x.86.175.9: bytes=56 Sequence=4 ttl=63 time=1 ms
    Reply from x.86.175.9: bytes=56 Sequence=5 ttl=63 time=1 ms

but i cannot ping from internet
ping x.86.175.9
PING x.86.175.9 (x.86.175.9) 56(84) bytes of data.

now if i add x.86.175.9/32 on x.208.153.201
i'll be able to ping this user can use internet.

-----------------------------
fib information
Destination/Mask   Nexthop         Flag  TimeStamp     Interface      TunnelID
x.86.175.9/32          x.208.153.201 DGHU  t[9572573]    Vlanif4000     0x0
u can try ping from internet
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Steelblue
Steelblue Created Oct 22, 2019 07:16:38 Helpful(0) Helpful(0)

Why static routes are required?
Is the default route not delivered on the S6720?
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Popeye_Wang
Popeye_Wang Admin Created Oct 22, 2019 08:02:42 Helpful(0) Helpful(0)

Posted by hashbang at 2019-10-17 11:08Posted by chenhui at 2019-10-17 11:08@hashbang hello,as you said, when the static route 10.10.10.1/3 ...

Do you mean that the 32-bit routes learned by OSPF on S6720 are advertised to the external network through BGP but cannot be accessed from the external network?
And after the static route to the 32-bit address is added to the S6720, the route is ok?
Am I right? If so, as #7 said, you may need to configure the default route or redistribute.
  • x
  • convention:

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