This article explains why there is a long delay in displaying ‘show system users’ and ‘traceroute’ outputs. To avoid a delay and print the output quickly, use the ‘no-resolve’ knob.

When entering show commands such as ‘show system users’ and ‘traceroute’ to a destination IP such as 4.4.4.4, there is a long delay in displaying the output.

This occurs because the command does a DNS lookup by default to resolve a name for the host IP. The ‘traceroute’ will try to do a DNS reverse name lookup by default. This will add a delay to the ‘traceroute’ , especially if you do not have a DNS server configured on the router or if it is not reachable from your router.

user@LAB> show system users               
USER     TTY      FROM                              LOGIN@   IDLE WHAT
user3    p0       sksiva-t61.jnpr.net               1:18AM     22  cli           
user3    p1       shell4.juniper.net                1:37AM      -  cli           
user3    p2       bigip.juniper.net                 1:40AM      -  cli           

To avoid a delay and display the output quickly, use the ‘no-resolve’ knob. The router will not do a DNS lookup to resolve a name, which will result in faster output display.

>show system users no-resolve
>traceroute 4.4.4.4 no-resolve

user@LAB> show system users no-resolve
USER     TTY      FROM                              LOGIN@  IDLE WHAT
user3    p0       172.22.18.117                    2:54AM     39 -cli (cli)    
user3    p1       172.22.18.119                    3:01AM      - -cli (cli)    
user3    p2       172.22.17.197                    3:08AM     11 -cli (cli)