bgp neighbor stuck in "Active" when configured in vrf

[terryfcc]

I'm trying to bring up a BGP session between two hosts via a VRF called RED (table id 10).
OS is CentOS 7.3 with Linux Kernel 4.9.47
iproute2 version is "iproute2-ss161212"

VRFs are created via iproute2.

And I have got the folowing error message in the log.

2017/09/14 21:22:15 BGP: 192.168.23.204 Binding to interface RED
2017/09/14 21:22:15 BGP: 192.168.23.204 [Event] Connect start to 192.168.23.204 fd 16
2017/09/14 21:22:15 BGP: 192.168.23.204 [FSM] Non blocking connect waiting result, fd 16
2017/09/14 21:22:15 BGP: 192.168.23.204 went from Idle to Connect
2017/09/14 21:22:15 BGP: 192.168.23.204 [Event] Connect failed (Resource temporarily unavailable)
2017/09/14 21:22:15 BGP: 192.168.23.204 [FSM] TCP_connection_open_failed (Connect->Active), fd 16
2017/09/14 21:22:15 BGP: 192.168.23.204 went from Connect to Active

My bgp configuration is below:
router bgp 65000 vrf RED
neighbor 192.168.23.204 remote-as 65000
neighbor 192.168.23.204 update-source 192.168.23.205

This is the output of "show ip route vrf RED"
Codes: K - kernel route, C - connected, S - static, R - RIP,
O - OSPF, I - IS-IS, B - BGP, P - PIM, E - EIGRP, N - NHRP,
T - Table, v - VNC, V - VNC-Direct, A - Babel,
> - selected route, * - FIB route

VRF RED:
K>* 0.0.0.0/0 [0/0] unreachable (ICMP unreachable)
C>* 192.168.23.0/24 is directly connected, eth0

This is the output of "ip route show table 10"
unreachable default
broadcast 192.168.23.0 dev eth0 proto kernel scope link src 192.168.23.205
192.168.23.0/24 dev eth0 proto kernel scope link src 192.168.23.205
local 192.168.23.205 dev eth0 proto kernel scope host src 192.168.23.205
broadcast 192.168.23.255 dev eth0 proto kernel scope link src 192.168.23.205
local 192.168.45.5 dev gre1 proto kernel scope host src 192.168.45.5

[terryfcc]

I have fixed the issue after putting in the below command in bash

sysctl -w net.ipv4.tcp_l3mdev_accept=1
More details can be found on this page: https://www.mjmwired.net/kernel/Documentation/networking/vrf.txt

[qlyoung]

this should probably go in our docs