NetWorker: Backup fails with: Unable to create session channel with nsrexecd on host client-name to execute command 'savefs ....

Unable to create session channel with nsrexecd on host client-name to execute command 'savefs -s server-name -c client-name'

Initial Steps:

• Check that nsrexecd is running on the client.

  • Linux: ps -ef | grep nsrexecd
    Windows: tasklist | findstr nsrexecd

    
     
• If client services are not running, start them and monitor for any service issues:

  • Linux: systemctl start networker
    Windows: net start nsrexecd

    
     
• Service startup issues can be monitored in the client's daemon.raw file:

  • Linux: /nsr/logs/daemon.raw
    Windows: C:\Program Files\EMC NetWorker\nsr\logs\daemon.raw

  • How to use nsr_render_log: NetWorker: How to use nsr_render_log
  • How to enable real-time log rendering: NetWorker: How to automatically render daemon.raw to daemon.log in real time
• Confirm that name resolution is working correctly from both the NetWorker server and client using nslookup. The FQDN, shortname, and IP should all return correctly.

Connectivity Troubleshooting:

• Check that nsradmin can connect from server to client and vice versa:

nsradmin -p nsrexecd -s client-name

• Check the port range on the server and client, with nsrports to confirm they match. The default service port range used by NetWorker is 7937-9936.
• On the NetWorker server, check which ports/processes are visible from the client: 

nsrrprcinfo -p client-name

PS C:\Windows\system32> nsrrpcinfo -p winsrvr2k16.emclab.local
PROGRAM VERSION PROTOCOL PORT SERVICE
100000  2       tcp      7938 nsrportmapper  Port Mapper
100000  2       udp      7938 nsrportmapper  Port Mapper
390436  1       tcp      8655 nsrexecd       GSS Authentication
390435  1       tcp      9220 nsrexecd       Resource Mirror
390113  1       tcp      7937 nsrexecd       Remote Execution
390440  1       tcp      9500 nsrexecd_nsrfa Remote File Access

• Check if there is a software firewall running on the client, and that if there is, the port range included the NetWorker ports:
  • Linux: 

    firewall-cmd --list-all

    A typical config, with the default NetWorker ports is:

# firewall-cmd --list-all
public (active)
  target: %%REJECT%%
  icmp-block-inversion: no
  interfaces: ens3
  sources:
  services:
  ports: 7937-9936/tcp
  protocols:
  forward: no
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks:
  rich rules:
        rule family="ipv4" source ipset="jump-servers" service name="ssh" accept

# firewall-cmd --list-all
public (active)
  target: %%REJECT%%
  icmp-block-inversion: yes
  interfaces: ens3
  sources:
  services:
  ports: 7936-7996/tcp
  protocols:
  forward: no
  masquerade: no
  forward-ports:
  source-ports:
  icmp-blocks: echo-reply echo-request
  rich rules:
        rule family="ipv4" source ipset="jump-servers" service name="ssh" accept

• It is recommended to use the default port range (7937-9936) when possible. The port range can be set using the nsrports command:

nsrports -S 7937-9936