Monitor Session VLAN Limitation?

[jnlawrence76]

I am trying to add the following but it seems that I can not add over 5 entries.  Is there a limitation as to how many you can add? I cannot do a range for all of the VLANS as I am setting this up for our IPS to monitor and there are Voice VLANs in between the data VLANs that I do not want to monitor:

Trying to put in :

monitor session 1 source vlan 1 - 32 , 40 , 48 , 56 , 64 , 72 , 80 , 88 , 96 , 100 , 104 , 112 , 120 , 128 , 136 , 144 , 152 , 160 , 168 , 176 , 184 , 192 , 200 , 208 , 216 , 240 - 242 , 250

But the 6509 will only take:

monitor session 1 source vlan 1 - 32 , 40 , 48 , 56 , 64

If I try to add an additional one past 64, it gives me a "Invalid input detected at '^' marker." error.

Thanks in advance.

[mgalazka · Accepted solution]

Jeremy,

You can accomplish this with multiple "monitor session 1 source vlan" config lines.  Please see my example below:

lab1(config)#monitor session 1 source vlan 2 , 4 , 6 , 8 , 10

lab1(config)#monitor session 1 source vlan 12 , 14 , 16 , 18 , 20

lab1(config)#do show run | i monitor

monitor session 1 source vlan 2 , 4 , 6 , 8 , 10

monitor session 1 source vlan 12 , 14 , 16 , 18 , 20

lab1(config)#do show monitor session 1

Session 1

---------

Type                   : Local Session

Source VLANs           :

    Both               : 2,4,6,8,10,12,14,16,18,20

Egress SPAN Replication State:

Operational mode       : Centralized

Configured mode        : Centralized (default)

lab1(config)#

Regards,

Matt

[jnlawrence76]

Perfect....worked like a charm.  Thanks for your prompt response.

[shepherd.magumo]

Thanks for the tip, very helpful!!

[FCU-JE]

Necromancing this topic just to add that it is still helpful and appears to be accurate in 2025 on IOS-XE 17.12.x software.

I could understand if there's some reason why they limit the number of VLAN ranges/entries that can be added in a single configuration command but I wish this were more intuitive to administrators at the very least in the `?` output.

I feel bad for admins (of which I consider myself one of) who for smaller environments still mostly rely on drafting configurations and then copy-pasting them in. It would be a very easy mistake for an admin to make to *think* that they can add as many VLAN entries/ranges they want in a single command but for this to end up not having the desired configuration.