Check Link Hook

This example demonstrates how to process outgoing NHRP traffic in a scenario using one Tunnel with GRE encapsulation.

Test Marks In NHRP Traffic

Description

In this scenario, a traffic policy was configured to log outgoing NHRP traffic, which is non-IP Layer 3 protocol. The special hook link-out can be used to process these outgoing frames.

Scenario

Step 1: Set the following configuration in DUT0 :

set interfaces ethernet eth0 address 192.168.100.10/24
set interfaces tunnel tun0 address 10.0.0.1/32
set interfaces tunnel tun0 encapsulation gre
set interfaces tunnel tun0 local-address 192.168.100.10
set interfaces tunnel tun0 nhrp
set interfaces tunnel tun0 traffic policy link-in LOG_NHRP
set interfaces tunnel tun0 traffic policy link-out LOG_NHRP
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'
set traffic policy LOG_NHRP rule 1 log prefix NHRP__
set traffic policy LOG_NHRP rule 1 selector NHRP_SEL
set traffic selector NHRP_SEL rule 1 ether-type 8193

Note

NHRP packets use ethertype 8193 (0x2001).

Step 2: Set the following configuration in DUT1 :

set interfaces ethernet eth0 address 192.168.100.20/24
set interfaces tunnel tun0 address 10.0.0.2/32
set interfaces tunnel tun0 encapsulation gre
set interfaces tunnel tun0 local-address 192.168.100.20
set interfaces tunnel tun0 nhrp holdtime 5
set interfaces tunnel tun0 nhrp nhs 10.0.0.1 nbma 192.168.100.10
set system login user admin authentication encrypted-password '$6$GSjsCj8gHLv$/VcqU6FLi6CT2Oxn0MJQ2C2tqnRDrYKNF8HIYWJp68nvXvPdFccDsT04.WtigUONbKYrgKg8d6rEs8PjljMkH0'

Step 3: Run command protocols ip show nhrp at DUT0 and check if output matches the following regular expressions:

tun0\s+dynamic\s+10\.0\.0\.2

Step 4: Run command system journal show | cat at DUT0 and check if output matches the following regular expressions:

\[NHRP__-1\] ACCEPT IN=tun0 OUT=\w+
\[NHRP__-1\] ACCEPT IN= OUT=tun0

Show output

Mar 23 15:26:28.173020 osdx systemd[1]: Started systemd-timedated.service - Time & Date Service.
Mar 23 15:26:28.000205 osdx systemd-timedated[872490]: Changed local time to Mon 2026-03-23 15:26:28 UTC
Mar 23 15:26:28.002084 osdx OSDxCLI[824268]: User 'admin' executed a new command: 'set date 2026-03-23 15:26:28'.
Mar 23 15:26:28.003523 osdx systemd-journald[2086]: Time jumped backwards, rotating.
Mar 23 15:26:28.346417 osdx systemd-journald[2086]: Runtime Journal (/run/log/journal/6b3b4e4818aa404284bc644df40f6904) is 1.9M, max 13.8M, 11.8M free.
Mar 23 15:26:28.347525 osdx systemd-journald[2086]: Received client request to rotate journal, rotating.
Mar 23 15:26:28.347576 osdx systemd-journald[2086]: Vacuuming done, freed 0B of archived journals from /run/log/journal/6b3b4e4818aa404284bc644df40f6904.
Mar 23 15:26:28.356963 osdx OSDxCLI[824268]: User 'admin' executed a new command: 'system journal clear'.
Mar 23 15:26:28.610919 osdx OSDxCLI[824268]: User 'admin' executed a new command: 'system coredump delete all'.
Mar 23 15:26:28.858859 osdx OSDxCLI[824268]: User 'admin' entered the configuration menu.
Mar 23 15:26:28.948665 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces ethernet eth0 address 192.168.100.10/24'.
Mar 23 15:26:29.040391 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 traffic policy link-out LOG_NHRP'.
Mar 23 15:26:29.136935 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 traffic policy link-in LOG_NHRP'.
Mar 23 15:26:29.228936 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 address 10.0.0.1/32'.
Mar 23 15:26:29.280499 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 encapsulation gre'.
Mar 23 15:26:29.374915 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 local-address 192.168.100.10'.
Mar 23 15:26:29.427530 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set interfaces tunnel tun0 nhrp'.
Mar 23 15:26:29.526067 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set traffic policy LOG_NHRP rule 1 log prefix NHRP__'.
Mar 23 15:26:29.578789 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set traffic policy LOG_NHRP rule 1 selector NHRP_SEL'.
Mar 23 15:26:29.664893 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'set traffic selector NHRP_SEL rule 1 ether-type 8193'.
Mar 23 15:26:29.734464 osdx OSDxCLI[824268]: User 'admin' added a new cfg line: 'show working'.
Mar 23 15:26:29.821590 osdx ubnt-cfgd[872527]: inactive
Mar 23 15:26:29.899861 osdx systemd[1]: Reloading frr.service - FRRouting...
Mar 23 15:26:29.914365 osdx watchfrr[872331]: [NG1AJ-FP2TQ] Terminating on signal
Mar 23 15:26:30.015321 osdx frrinit.sh[872557]: Stopped watchfrr.
Mar 23 15:26:30.016300 osdx frrinit.sh[872557]: Starting watchfrr with command: '  /usr/lib/frr/watchfrr  -d  --min-restart-interval 1 --max-restart-interval 600 --timeout 600 --restart-timeout 600 zebra mgmtd nhrpd staticd'.
Mar 23 15:26:30.022296 osdx watchfrr[872575]: [T83RR-8SM5G] watchfrr 10.4.1 starting: vty@0
Mar 23 15:26:30.022341 osdx watchfrr[872575]: [QDG3Y-BY5TN] zebra state -> up : connect succeeded
Mar 23 15:26:30.022362 osdx watchfrr[872575]: [QDG3Y-BY5TN] mgmtd state -> up : connect succeeded
Mar 23 15:26:30.022396 osdx watchfrr[872575]: [ZCJ3S-SPH5S] nhrpd state -> down : initial connection attempt failed
Mar 23 15:26:30.022399 osdx watchfrr[872575]: [QDG3Y-BY5TN] staticd state -> up : connect succeeded
Mar 23 15:26:30.022563 osdx watchfrr[872575]: [YFT0P-5Q5YX] Forked background command [pid 872576]: /usr/lib/frr/watchfrr.sh restart nhrpd
Mar 23 15:26:30.026202 osdx frrinit.sh[872576]: Cannot stop nhrpd: pid file not found
Mar 23 15:26:30.027125 osdx watchfrr.sh[872581]: Cannot stop nhrpd: pid file not found
Mar 23 15:26:30.036755 osdx zebra[733918]: [V98V0-MTWPF] client 36 says hello and bids fair to announce only nhrp routes vrf=0
Mar 23 15:26:30.045983 osdx frrinit.sh[872586]: sh: line 1: ipsec: command not found
Mar 23 15:26:30.046984 osdx watchfrr[872575]: [QDG3Y-BY5TN] nhrpd state -> up : connect succeeded
Mar 23 15:26:30.046992 osdx watchfrr[872575]: [KWE5Q-QNGFC] all daemons up, doing startup-complete notify
Mar 23 15:26:30.047409 osdx frrinit.sh[872557]: Started watchfrr.
Mar 23 15:26:30.159480 osdx systemd[1]: Reloaded frr.service - FRRouting.
Mar 23 15:26:30.195536 osdx kernel: 8021q: adding VLAN 0 to HW filter on device eth0
Mar 23 15:26:30.243756 osdx WARNING[872679]: No supported link modes on interface eth0
Mar 23 15:26:30.245193 osdx modulelauncher[872679]: osdx.utils.xos cmd error: /sbin/ethtool -A eth0 autoneg on
Mar 23 15:26:30.245207 osdx modulelauncher[872679]: Command '/sbin/ethtool -A eth0 autoneg on' returned non-zero exit status 76.
Mar 23 15:26:30.246791 osdx modulelauncher[872679]: osdx.utils.xos cmd error: /sbin/ethtool -s eth0 autoneg on advertise Pause off Asym_Pause off --
Mar 23 15:26:30.246801 osdx modulelauncher[872679]: Command '/sbin/ethtool -s eth0 autoneg on advertise Pause off Asym_Pause off --' returned non-zero exit status 75.
Mar 23 15:26:30.271637 osdx (udev-worker)[872707]: Network interface NamePolicy= disabled on kernel command line.
Mar 23 15:26:30.503941 osdx cfgd[1828]: [824268]Completed change to active configuration
Mar 23 15:26:30.515943 osdx OSDxCLI[824268]: User 'admin' committed the configuration.
Mar 23 15:26:30.543996 osdx OSDxCLI[824268]: User 'admin' left the configuration menu.
Mar 23 15:26:32.167606 osdx OSDxCLI[824268]: User 'admin' executed a new command: 'protocols ip show nhrp'.
Mar 23 15:26:33.036423 osdx kernel: [NHRP__-1] ACCEPT IN=tun0 OUT= MAC=45:00:00:74:a4:8b:40:00:40:2f:4c:60:c0:a8:64:14:c0:a8:64:0a:00:00:20:01
Mar 23 15:26:33.039537 osdx kernel: [NHRP__-1] ACCEPT IN= OUT=tun0 MAC=45:01:00:00:00:00:40:00:40:2f:00:00:c0:a8:64:0a:c0:a8:64:14:00:00:20:01
Mar 23 15:26:33.039572 osdx kernel: [NHRP__-1] ACCEPT IN=tun0 OUT=eth0 MAC=00:01:08:00:00:00:00:00:00:40:00:70:2b:43:00:34:01:04:04:00:04:04:00:02
Mar 23 15:26:34.036900 osdx kernel: [NHRP__-1] ACCEPT IN=tun0 OUT= MAC=45:00:00:74:a4:a2:40:00:40:2f:4c:49:c0:a8:64:14:c0:a8:64:0a:00:00:20:01
Mar 23 15:26:34.039527 osdx kernel: [NHRP__-1] ACCEPT IN= OUT=tun0 MAC=45:01:00:00:00:00:40:00:40:2f:00:00:c0:a8:64:0a:c0:a8:64:14:00:00:20:01
Mar 23 15:26:34.039549 osdx kernel: [NHRP__-1] ACCEPT IN=tun0 OUT=eth0 MAC=00:01:08:00:00:00:00:00:00:40:00:70:2b:42:00:34:01:04:04:00:04:04:00:02
Mar 23 15:26:34.243810 osdx OSDxCLI[824268]: User 'admin' executed a new command: 'protocols ip show nhrp'.

Step 5: Run command traffic policy show at DUT0 and check if output matches the following regular expressions:

1\s+NHRP_SEL\s+\b[^0]\d*