We have a Juniper SRX talking to a Dell.

One of the BFD sessions has a problem. The Juniper reports it as being up, the Dell reports it as being down.

In the BFD trace on the Juniper, I see messages like the following:

Packet from 10.xxx.xxx.9 to (null) (ifl 87, rtbl 5), discr 0x0, label 0, matches wrong session

10.xxx.xxx.9 is the Dell.

I don't know where discr 0x0 comes from.

When I do show bfd session extensive, I get:

Local discriminator 220, remote discriminator 4

The other obvious difference between this BFD session and other, working, sessions is the last line.

The good sessions show:

Echo mode disabled/inactive Session ID: 0x0

The down session shows:

Echo mode disabled/inactive, no-absorb, no-refresh, update-adj
 Session ID: 0x0

Any suggestions on where I should look next?


protocols {
  bgp {
    bfd-liveness-detection {
      minimum-interval 1000;
    group group_BGP {
      type external;
      import BGP;
      export [ BGP ... ];
      peer-as 64444;
      local-as 64567;
      neighbor 10.xxx.xxx.9 {
        local-address 10.xxx.xxx.12;
        authentication-key /* SECRET-DATA */; ## SECRET-DATA
        peer-as 64444;
      neighbor 10.xxx.xxx.10 {
        local-address 10.xxx.xxx.12;
        authentication-key /* SECRET-DATA */; ## SECRET-DATA
        peer-as 64444;

    security-zone sec_zone1 {
        protocols {


  LocalAddr                          RemoteAddr                         Interface  State Rx-int Tx-int Mult VRF Clients
* 10.xxx.xxx.9                       10.xxx.xxx.12                      Vl 234     Down  1000   1000   3    1      B

  LocalAddr                          RemoteAddr                         Interface  State Rx-int Tx-int Mult VRF Clients
* 10.xxx.xxx.10                      10.xxx.xxx.12                      Vl 234     Up    1000   1000   3    2      B
  • 2
    Please provide configurations of both devices.
    – Teun Vink
    Feb 4, 2019 at 6:13
  • Added some config - there really doesn't seem to be much ability to misconfig this - except the authentication key, I guess. There's no obvious difference in config between this BFD session and the working BFD sessions. BGP with this peer is working and there are no obvious problems with pinging, etc. Feb 6, 2019 at 1:09
  • I find it interesting that we have two Juniper-to-Other BFD problems in a few days: networkengineering.stackexchange.com/q/56552/8499
    – Ron Maupin
    Feb 6, 2019 at 1:50
  • It seems (from the limited details on interface configurations) that you're setting up two sessions between two devices with VRFs on one side. More details on the interface configurations and VRFs could help people to understand your setup better and possibly help you find a solution.
    – Teun Vink
    Feb 6, 2019 at 5:59
  • @BenAveling I doubt it, but are the BGP peers in different security zones? Do you have NAT happening for any of these peer connections? Feb 6, 2019 at 13:22


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