BGP next-hop 127.0.0.1 and 0.0.0.0

Created: Dec 23, 2019 09:34:23Latest reply: Dec 24, 2019 01:03:02 189 8 0 0
  Rewarded HiCoins: 0 (problem resolved)

hello guys, I found something strange when I check the BGP routing table.


BGP next hop


As the figure display, the nexthop of the BGP routes for the second and third routing items are 127.0.0.1 and 0.0.0.0, why they are different from each other? Do you guys ever noticed this?

Any suggestions would be appreciate.

Thanks.

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chenhui
Admin Created Dec 23, 2019 09:37:34 Helpful(1) Helpful(1)

@user_3534491 hello,
it's normal. For BGP, when advertise the routes with network, the next hop would be set to 0.0.0.0, and if you aggregate the routes manually, the next hop for the aggregate route would be 127.0.0.1.
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chenhui
chenhui Admin Created Dec 23, 2019 09:37:34 Helpful(1) Helpful(1)

@user_3534491 hello,
it's normal. For BGP, when advertise the routes with network, the next hop would be set to 0.0.0.0, and if you aggregate the routes manually, the next hop for the aggregate route would be 127.0.0.1.
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umaryaqub
umaryaqub MVE Created Dec 23, 2019 09:39:40 Helpful(0) Helpful(0)

Deleted.
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A%20network%20professional%20eager%20to%20learn%20and%20help.I%20have%208%20years%20of%20network%20experience%20and%20I%20am%20working%20with%20Huawei%20VAP%20and%20looking%20after%20IP%20Projects%20design.
user_3534491
user_3534491 Created Dec 23, 2019 09:42:21 Helpful(0) Helpful(0)

Posted by chenhui at 2019-12-23 09:37 @user_3534491 hello,it's normal. For BGP, when advertise the routes with network, the next hop would ...
Thanks. then why they are marked with the different next hop, why not using 127.0.0.1 or 0.0.0.0 for both?
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user_3534491
user_3534491 Created Dec 23, 2019 09:43:36 Helpful(0) Helpful(0)

Sorry, but I didn't get what you deleted.
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chenhui
chenhui Admin Created Dec 23, 2019 09:51:14 Helpful(0) Helpful(0)

Posted by user_3534491 at 2019-12-23 09:42 Thanks. then why they are marked with the different next hop, why not using 127.0.0.1 or 0.0.0.0 f ...
I think 0.0.0.0 indicates the BGP wouldn't handle the packets, as we talked before, next hop would be set to 0.0.0.0 when advertise routes with network, then the advertised route must be learned from other protocol with lower preference, or it might be connected directly. While aggregate the routes, there might be other routes which not belongs to the part described before, then the BGP would handle these routes, and next hop 127.0.0.1 means the packets would be sent to CPU.
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umaryaqub
umaryaqub MVE Created Dec 23, 2019 10:23:11 Helpful(0) Helpful(0)

Posted by user_3534491 at 2019-12-23 06:43 Sorry, but I didn't get what you deleted.
Basically I answered the same as Chenhui.

It is default behavior and you see after first best route, next is set to loopback address and 0.0.0.0 means that any route that is defined in less preferred protocol will be used. You can see that both are marked as Best and Valid.
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A%20network%20professional%20eager%20to%20learn%20and%20help.I%20have%208%20years%20of%20network%20experience%20and%20I%20am%20working%20with%20Huawei%20VAP%20and%20looking%20after%20IP%20Projects%20design.
user_3534491
user_3534491 Created Dec 24, 2019 01:02:35 Helpful(0) Helpful(0)

Posted by chenhui at 2019-12-23 09:51 I think 0.0.0.0 indicates the BGP wouldn't handle the packets, as we talked before, next hop would ...
OK, thanks.
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user_3534491
user_3534491 Created Dec 24, 2019 01:03:02 Helpful(1) Helpful(1)

Posted by umaryaqub at 2019-12-23 10:23 Basically I answered the same as Chenhui. It is default behavior and you see after first best rout ...
Thanks for your supporting.
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