recommendation banner motd size

[fmerkle]

hi,

are there any recommendations about the size for the banner motd?

In the past we had some trouble with too big banner motd text (more than 30 lines). we were unable to connect to the switch via telnet. We had no problems with the banner motd when we connected via console port.

thank you

frank

[Georg Pauwen]

Hello,

I do not know of any specific size limitation, but possibly your CPU is too busy to handle the banner in connection with a TELNET, you can try and change the CPU percentage available to system tasks with the following command:

The following example makes 20 percent of the CPU available for process tasks:

Router(config)# scheduler allocate 2000 500

HTH,

GP

[smcquerry]

Yes there are some specific size limitations to banners based on operating system and/or device.

If the device is running CatOS the banner is limited to 3,070 characters.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_6_3/cmd_ref/ses_sete.htm#21926

For a 1900 series switch the limit is 400 characters or 20 lines.

http://www.cisco.com/en/US/partner/products/hw/switches/ps574/products_command_reference_chapter09186a008007d21d.html#xtocid159274

For other IOS devices, there is no documented limit, however there are limitations based on the amount of NVRAM available. Each IOS devices has a different amount of NVRAM available and it is conceivable that the banner can be so large that it fills up the NVRAM. Having stated that it is unlikely that anyone would have a banner that large.

Given all the stated information however, I do not see a reason where the banner would prevent you from connecting to a telnet session.