what does ip tftp source-interface <interface> means??

[penghon]

Ugh, what does the abovementioned line do?
Cisco explanation is:

"Allows a user to select the interface whose address will be used as the source address for TFTP connections"

What in the world does it mean? How is this gonna affect my switch, which is not the interface mentioned above, from tftp into the tftp server?

 

[BuckWeet]

Its there in case you have access-lists or something where you limit tftp connections to your server. You can use this so it will use that source address upon connecting to the server just for that reason.


BuckWeet

 

[MJewell]

Mainly it's for starting the TFTP session from a Vlan by forcing it to route from a specific IP...


-Mike

 

[penghon]

er...i am still kenna confused. Does this means that for my ACL i will be just permitting that single source address to access the tftp server even though i can multiple different network nodes accessing the tftp server? My explanation does not make any sense...so it has to be wrong...anyone care to explain further?

 

[MJewell]

no, it's more of a edfault command, if you specify
ip tftp source-interface Vlan540

then the router would allways choose the IP address associated with Vlan540 for it's source address. If your TFTP server was set to only allow traffic from a specific subnet of addresses, you may want to force your IOS routers and switches to always use this one port for TFTP to prevent it from choosing a wrong interface and being denied by the server.

Here's what the book says for the whole command:


ip tftp source-interface
To specify the IP address of an interface as the source address for TFTP connections, use the ip tftp source-interface global configuration command. To return to the default, use the no form of this command.

ip tftp source-interface interface
no ip tftp source-interface
Syntax Description

interface
The interface whose address is to be used as the source for TFTP connections.

Defaults

The address of the closest interface to the destination as the source address.

Usage Guidelines

Use this command to set the IP address of an interface as the source for all TFTP connections.

If the specified interface is not up, the Cisco IOS software selects the address of the interface closest to the destination as the source address.