Error: Hold timer expired

[Marek Królikowski]

Hello guys,
I buy VPS with BGP and try setup BGP session but got strange problem.
VPS support send me this information to setup session:
"Please peer with 185.144.XXX.YYY, you will need to enable eBGP multihop.
Our ASN is XXXX.
The IPv6 peer address is 2a04:9dc0:XX:YYY::1"

My bird configuration looks like this:
---------------------------------------
router id 85.204.XXX.YYY;
# debug protocols all;
protocol device {
scan time 10;
}

protocol static {
        route 2a04:9dc0:XX:YYY::1/128 via "eth0";
}

protocol kernel {
        device routes;
        import none;
        scan time 15;
        export filter {
        if net = 2a04:9dc0:XX:YYY::1/128 then reject;
        if source = 2a04:9dc0:XX:YYY::1/128 then reject;
        accept;
        };
}

protocol bgp Romania
{
    description "Romania link local";
    local as YYYYY;
    source address 2a04:9dc0:X:YY::f0;
    graceful restart on;
    default bgp_local_pref 200;
    multihop 2;
    neighbor 2a04:9dc0:XX:YYY::1 as XXXX;
    import filter {
    if net = 2a04:9dc0:XX:YYY::1/128 then reject;
    if source = 2a04:9dc0:XX:YYY::1/128 then reject;
    if bgp_path.len > 49 then reject;
    accept;
    };
    export filter {
    if net = 2a07:1c44:3511::/48 then accept;
    reject;
};
}
---------------------------------------

In logs got it:
Aug  8 16:21:41 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:24:02 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:27:07 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:35:58 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:37:25 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:39:27 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:41:57 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 16:56:19 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:00:29 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:06:10 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:09:58 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:13:01 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:15:08 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:18:15 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:22:58 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:29:17 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:31:49 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:35:17 ro-bgp bird6: Romania: Error: Hold timer expired
Aug  8 17:40:08 ro-bgp bird6: Romania: Error: Hold timer expired


root at bgp:~# birdc6 show protocols all Romania
BIRD 1.6.3 ready.
name     proto    table    state  since       info
Romania  BGP      master   up     16:22:37    Established
  Description:    Romania link local
  Preference:     100
  Input filter:   (unnamed)
  Output filter:  (unnamed)
  Routes:         11560 imported, 5 exported, 11560 preferred
  Route change stats:     received   rejected   filtered    ignored
accepted
    Import updates:          11560          0          0          0
11560
    Import withdraws:            0          0        ---          0
0
    Export updates:          11586      11560         21        ---
5
    Export withdraws:            0        ---        ---        ---
0
  BGP state:          Established
    Neighbor address: 2a04:9dc0:XX:YYY::1
    Neighbor AS:     XXXX
    Neighbor ID:      185.144.XXXX
    Neighbor caps:    refresh restart-aware AS4
    Session:          external multihop AS4
    Source address:   2a04:9dc0:X:YY::f0;
    Hold timer:       27/90
    Keepalive timer:  23/30

root at bgp:~# birdc6 show protocols all Romania
BIRD 1.6.3 ready.
name     proto    table    state  since       info
Romania  BGP      master   start  16:24:05    Idle          BGP Error: Hold
timer expired
  Description:    Romania link local
  Preference:     100
  Input filter:   (unnamed)
  Output filter:  (unnamed)
  Routes:         0 imported, 0 exported, 0 preferred
  Route change stats:     received   rejected   filtered    ignored
accepted
    Import updates:              0          0          0          0
0
    Import withdraws:            0          0        ---          0
0
    Export updates:              0          0          0        ---
0
    Export withdraws:            0        ---        ---        ---
0
  BGP state:          Idle
    Neighbor address: 2a04:9dc0:XX:YYY::1
    Neighbor AS:      XXXX
    Error wait:       57/120
    Last error:       BGP Error: Hold timer expired


Best Regards
Marek Krolikowski