The kernel protocol import filter is missing the accept; statement after you selectively filter some prefices out. BIRD doesn't know whether you want to accept or reject these routes. It also shall warn you in log. Do you have any log line saying something about filter not rejecting nor accepting? Maria On December 10, 2019 10:09:06 PM GMT+01:00, wax xitau <waxitau@gmail.com> wrote:
Hi,
Prefixes sent over a eBGP session are getting rejected "by protocol" as can be seen in the logs below. The prefixes are "added" and then get "rejected" by protocol. This means that they are visible using the "show route protocol <protocol>" but not "show route all" (and therefore impossible to push them to the kernel routing table).
// logs
2019-12-10 21:15:00.774 <TRACE> pe1: BGP session established 2019-12-10 21:15:00.774 <TRACE> pe1: State changed to up 2019-12-10 21:15:00.774 <TRACE> pe1: Sending END-OF-RIB 2019-12-10 21:15:00.984 <TRACE> pe1: Got UPDATE 2019-12-10 21:15:00.984 <TRACE> pe1 > *added [best] 10.2.34.0/24 <http://10.2.34.0/24> unicast* 2019-12-10 21:15:00.984 <TRACE> pe1 < *rejected by protocol 10.2.34.0/24 <http://10.2.34.0/24> unicast* 2019-12-10 21:15:00.984 <TRACE> pe1: Got UPDATE 2019-12-10 21:15:00.984 <TRACE> pe1 > *added [best] 10.1.12.0/24 <http://10.1.12.0/24> unicast* 2019-12-10 21:15:00.984 <TRACE> pe1 < *rejected by protocol 10.1.12.0/24 <http://10.1.12.0/24> unicast* 2019-12-10 21:15:00.984 <TRACE> pe1: Got UPDATE 2019-12-10 21:15:00.984 <TRACE> pe1: Got END-OF-RIB
Tcp dump of the corresponding update message(s):
// tcpdump
21:18:59.652705 IP (tos 0xc0, ttl 1, id 7035, offset 0, flags [none], proto TCP (6), length 177) *192.168.254.1*.bgp > 192.168.254.0.41073: Flags [P.], cksum 0x4356 (correct), seq 83:208, ack 73, win 16384, options [nop,nop,TS val 2249949122 ecr 1355158152], length 125: BGP Update Message (2), length: 51 Origin (1), length: 1, Flags [T]: IGP 0x0000: 00 AS Path (2), length: 10, Flags [T]: 65001 65500 0x0000: 0202 0000 fde9 0000 ffdc Next Hop (3), length: 4, Flags [T]: 192.168.254.1 0x0000: c0a8 fe01 Updated routes: 10.1.12.0/24 Update Message (2), length: 51 Origin (1), length: 1, Flags [T]: Incomplete 0x0000: 02 AS Path (2), length: 10, Flags [T]: 65001 65500 0x0000: 0202 0000 fde9 0000 ffdc Next Hop (3), length: 4, Flags [T]: *192.168.254.1* 0x0000: c0a8 fe01 Updated routes: 10.2.34.0/24 Update Message (2), length: 23 End-of-Rib Marker (empty NLRI)
The bgp session is over directly connected interfaces and the NLRI prefix next hops are therefore directly connected.
// Configuration:
protocol bgp pe1 { debug all; description "ebgp"; hold time 90; local 192.168.254.0 as my_asn; neighbor 192.168.254.1 as peer_asn; direct; interpret communities off; ipv4 { table t_pe1; import all; export none; gateway direct; }; }
protocol device { scan time 10; };
protocol direct { ipv4; };
protocol kernel { scan time 10; learn; persist; ipv4 { import filter { if net ~ [0.0.0.0/0, 192.168.255.0/24] then reject; }; }; }
// relevant show results
bird> *show route protocol pe1* Table t_pe1: *10.2.34.0/24 <http://10.2.34.0/24>* unicast [pe1 21:46:13.530] * (100) [AS65500?] via 192.168.254.1 on ens5 *10.1.12.0/24 <http://10.1.12.0/24>* unicast [pe1 21:46:13.530] * (100) [AS65500i] via 192.168.254.1 on ens5 bird>
bird> *show route all* Table master4: 172.16.0.11/32 unicast [rt_nh 20:25:25.379] * (200) via 192.168.254.1 on ens5 Type: static univ 192.168.254.2/31 unicast [direct1 20:56:03.498] * (240) dev ens6 Type: device univ 192.168.254.0/31 unicast [direct1 20:56:03.498] * (240) dev ens5 Type: device univ 192.168.255.0/24 unicast [direct1 20:56:03.498] * (240) dev ens4 Type: device univ 172.16.0.33/32 unicast [rt_nh 20:25:25.379] * (200) via 192.168.254.3 on ens6 Type: static univ
Thanks,
-- Sent from my Android device with K-9 Mail. Please excuse my brevity.