Cisco IOS – “service linenumber”

4 01 2007

Just came across something I’d not noticed before in IOS. Apparently this has been around since IOS 10… There’s a command called “service linenumber” – it prints the line number and name of the device you are telnetting to, which can help in avoiding confusion.

Here’s a capture of what I did in my lab – telnet to R4 from R5, enter the command in global config, and telnet back in again to see the difference (note the name and line-number just after the second “open”):

Trying ... Open

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Rack1R4#conf t
Enter configuration commands, one per line.  End with CNTL/Z.

Rack1R4(config)#service linenumber

[Connection to closed by foreign host]

Now, telnet back again – this time note the annoucement of the router name and line number after the session opens:

Rack1R5#telnet ... Open

Rack1R4 line 322

User Access Verification




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