February 2025 - Bird-users

Bird v3 BGP route selection
by Nigel Kukard 25 Feb '25

25 Feb '25

Hi there, I'm wondering if someone can point out how the best path is being selected below in Bird 3.0.1? In Bird v2 the route via 100.201.0.2 was selected. With the exact same configuration in Bird v3, the route via 100.201.0.4 is being selected. In this case R1 is connected to R2. Both with the same ASN. The below table is the table I have facing R2. In terms of my routing tables... - originate4 =exports to=> bgp4 - static4 =exports to=> master4 - master4 <=exports/imports=> bgp4 - bgp4 <=exports/imports=> t_bgp4_AS65000_r2_peer (below) 1007-Table t_bgp4_AS65000_r2_peer: 0.0.0.0/0 unicast [bgp_originate4 2025-02-24 23:21:13] * (200) via 100.201.0.4 on eth2 1012- preference: 200 source: static bgp_local_pref: 930 bgp_large_community: (65000, 3, 1) 1008- Internal route handling values: 0L 24G 0S id 1 1007- unicast [static4 2025-02-24 23:21:13] (200) via 100.201.0.2 on eth2 1012- preference: 200 source: static bgp_local_pref: 940 bgp_large_community: (65000, 3, 1) (65000, 5000, 1) 1008- Internal route handling values: 0L 22G 0S id 6 Kind Regards Nigel

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How to filter VPN4 address using route-map
by Ramanathan Selvamani 24 Feb '25

24 Feb '25

Hi Team, I would like to filter a VPN4 address using route-map. For example, I have the below VPN4 address learnt through BGP neighbor on "L2VPN EVPN" channel. Table vpntab4: 1:222 90.0.0.0/24 unicast [EVPN_4_4_4_4 2025-02-21] * (160) 1:100 60.0.0.0/24 unicast [BGP_4_4_4_4 17:45:37.617 from 4.4.4.4] * E (156/1) [AS400?] 4.4.4.4:222 70.0.0.0/24 unicast [BGP_4_4_4_4 17:45:37.617 from 4.4.4.4] * E (156/1) [AS400?] 1:111 151.1.1.0/24 unicast [EVPN_4_4_4_4 2025-02-21] * (160) I want to create a route-map to accept only 1:100 60.0.0.0/24 and reject all the rest. When I tried the below configuration in route-map, I got a syntax error on the below line. if(net ~ [1:100 60.0.0.0/24]) then { return 2;} Similarly, is there any way to filter the VPN4 address using its RD value ? Thanks, Ramanathan

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IPv6 prefix is not stored to kernel when multipath is enabled in 1.6.8
by Jimmy Lim 20 Feb '25

20 Feb '25

Hi guys, I have multipath enabled on bird6 running in old 1.6.8. I discovered that the IPv6 prefix failed to be installed properly in the kernel with more than 1 path and when multipath is enabled. syslog message: > Feb 9 23:54:31 x40-n bird6: kernel1 < replaced fcdf::/16 multipath > Feb 9 23:54:53 x40-n bird6: kernel1: fcdf::/16: reinstalling > Feb 9 23:55:53 x40-n bird6: kernel1: fcdf::/16: reinstalling > Feb 9 23:56:53 x40-n bird6: kernel1: fcdf::/16: reinstalling The IPv6 prefix is installed properly if I remove multipath in bird6: > # merge paths on; But then it means the path won't be shared with the rest of the path. syslog message: > Feb 9 23:57:15 x40-n bird6: kernel1 < added fcdf::/16 dev wg2 > Feb 9 23:57:15 x40-n bird6: kernel1: fcdf::/16: reinstalling > Feb 9 23:58:15 x40-n bird6: kernel1: fcdf::/16: seen > Feb 9 23:59:16 x40-n bird6: kernel1: fcdf::/16: seen Do you guys encounter this issue or is there any other configuration needed? The multipath works well in IPv4/bird. Thanks, Jimmy

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[PATCH] OSPF: Fix inverted path comparison for external
by Mantas Mikulėnas 18 Feb '25

18 Feb '25

From: Mantas Mikulėnas <grawity(a)gmail.com> For an ordinary E1 or E2 route exported by another Bird2 router in the same area, it was consistently choosing a 10000+ metric path through another area, despite having a direct 10-metric path to the origin in the same backbone area. It seems that this was because the rule 16.2 metric comparison was backwards and always chose highest metric. Note - the patch is probably *not* 100% right; I am not very sure whether both checks are backwards or only the orta_pref() one. It's merely my first successful attempt at fixing the issue (which only affected Bird, not any other OSPFv2 implementation I have here). Regardless, it did happen to fix the issue I was having, and now Bird2 chooses the path I expect it to choose: Before: Table master4: 172.20.0.0/14 unicast [ospf4 10:09:35.865] * E2 (150/10080/100) [31.220.42.129] via 10.147.255.10 on homegw Type: OSPF-E2 univ OSPF.metric1: 10080 OSPF.metric2: 100 OSPF.tag: 0x00000000 OSPF.router_id: 31.220.42.129 After: Table master4: 172.20.0.0/14 unicast [ospf4 12:48:02.452] * E2 (150/30/100) [31.220.42.129] via 10.147.240.122 on gre-land Type: OSPF-E2 univ OSPF.metric1: 30 OSPF.metric2: 100 OSPF.tag: 0x00000000 OSPF.router_id: 31.220.42.129 --- proto/ospf/rt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/proto/ospf/rt.c b/proto/ospf/rt.c index d7753ce0a..c6bf5699e 100644 --- a/proto/ospf/rt.c +++ b/proto/ospf/rt.c @@ -200,7 +200,7 @@ orta_compare_asbr(const struct ospf_proto *p, const orta *new, const orta *old) if (!p->rfc1583) { - r = epath_preferred(new) - epath_preferred(old); + r = epath_preferred(old) - epath_preferred(new); if (r) return r; } @@ -242,7 +242,7 @@ orta_compare_ext(const struct ospf_proto *p, const orta *new, const orta *old) /* 16.4 (6c) - if not RFC1583, prefer routes with preferred ASBR/next_hop */ if (!p->rfc1583) { - r = orta_pref(new) - orta_pref(old); + r = orta_pref(old) - orta_pref(new); if (r) return r; } -- 2.48.1

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No `hostname` within `protocol`?
by Bernd Naumann 12 Feb '25

12 Feb '25

Hey! I wanted to set `hostname "foo";` within `template bgp ... { ... };` and got `syntax error, unexpected HOSTNAME`. As a workaround I can set the hostname on the global level but I would like to see that's possible to set hostname on a protocol level. My use-case (that's why I stumbled upon it) is that I've been connected to dn42 and wanted to announce `cpe.bernd.dn42` on my peers and not just the systems `cpe`, or it's unhelpful fqdn `cpe.home.arpa`.[1] I'm running BIRD version 2.15.1 on OpenWrt 23.05.5. Thanks! Bernd [1] Yes, I do really like `home.arpa.`.

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Several crashes in 3.0.1
by Yureka 10 Feb '25

10 Feb '25

After deploying bird 3.0.1, the bird process keeps crashing on several of my routers, which had never crashed before on bird 2.x. Within ~5min, I've seen the bird process crash with SIGABRT 27 times: 16x `Withdrawn route never seen before` 8x `Assertion '!rt_export_feed_active(&c->reimporter)' failed at nest/proto.c:756` 2x `Assertion 'rt_export_get_state(&c->out_req) == TES_DOWN' failed at nest/proto.c:755` 1x `Assertion '!old' failed at nest/rt-table.c:1510` My config is using a mix of Babel with RTT extensions, OSPF, iBGP and eBGP. "withdrawn route never seen before" sure sounds like one of my peers is misbehaving but 1) this should not crash bird 2) it should provide more information about which peer is misbehaving I can not judge which of the other assertions are errors about the bird-internal state which should never happen in the first place, or which are caused by bad peer behaviour (which, again, should not crash bird). Best regards, Yureka

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How to upgrade version Bird to 2.15.1
by Nguyen Van Nhan 02 Feb '25

02 Feb '25

Dear Bird Community, I have installed BIRD and tested the configurations related to the operation of this application. I have some questions during the BIRD deployment process, I hope you will give me specific instructions for editing and optimizing in operation. I am installing the default Bird version 2.0.8 on Ubuntu LTS 22.04 operating system 1. Can you provide me with detailed instructions to upgrade Bird to the latest version 2.15.1? I have tried to upgrade but when performing the operation in birdc, it still shows that it is at version 2.0.8. 2. Does Bird support BMP protocol in the latest version? We are researching to use BMP on Bird to get monitoring data via OpenBMP. Is it possible? Thanks and best regards, Nhan Nguyen Email: nhannv(a)vnnic.vn<mailto:nhannv@vnnic.vn> Mobile: +84 905 674 854

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