Find and transfer file with connected devices in closed network

[chanlim]

I want to use the Cisco router as a server to transfer files from/to Linux devices.

I found the copy command.

But I am not sure what is the IP address of both devices.

Both are not connected to the Internet and I can connect two devices using an ethernet cable or a USB cable.

When I connect them using an ethernet cable, en0 shows inet6 address in Linux. Can I use this IPv6 address in copy command?

And in the router, 'show arp interface' and 'show cdp interface' don't show any connected devices.

[Hector Gustavo Serrano Gutierrez · Accepted solution]

The Cisco Routers (ISR & ASR family of Routers) can be used as FTP, TFTP, SCP, RCP, etc as clients.

These Cisco IOS Routers can be a TFTP Server. Try with Router(config)# tftp-server ...

As a side note, Cisco Nexus Switches (NX-OS) can be a SCP Server.

You can check the IP address assigned to Layer 3 interfaces with show ip interface brief command on Cisco IOS & IOS-XE Routers.

You should be able to use IPv6 addresses to connect to the file Server (I have not tested it myself though).

show arp is only for IPv4.

With IPv6, you need to use show ipv6 neighbor as instead of show arp.

show cdp neighbor is mostly for Cisco devices, unless you know for sure that the network device the Cisco Router directly connects to is also running CDP protocol.

LLDP is an alternative to CDP which can be found on non-Cisco devices.

You may also find this doc helpful:

How To Copy a System Image from One Device to Another

Regards.

[chanlim]

Thanks for your answer.

It seems that the Linux device is not well connected to the router.

In the result of 'show ip interface brief',

Interface                   IP-Address      OK? Method Status                Protocol

FastEthernet0/0/1     unassigned      YES   unset     up                   up

FastEthernet port1 is up, but IP-address is unassigned.

And 'show ipv6 neighbors' doesn't show any result.

Do I need to do something else than connecting Ethernet cable?

[Harold Ritter]

The fact that "show ipv6 neighbor" does not show any output could be due to the fact that IPv6 is not enabled on the interface.

Could you do a "show ipv6 int FastEthernet0/0/1"

Regards,

[chanlim]

'show ipv6 int FastEthernet0/0/1' also doesn't show any output.

[Hector Gustavo Serrano Gutierrez]

On Routers, you most of the times need to manually assign an IPv4 address to your interface.

configure terminal
!
interface FastEthernet0/0/1
 ip address 192.168.1.50 255.255.255.0
 no shutdown
!
exit

If the interface is not allowing you to configure the IP address, it is because it is a layer 2 interface (in "switching mode" as opposed to "routing mode").

In that case do:

configure terminal
!
interface FastEthernet0/0/1
 switchport access vlan 1
!
interface vlan1
 ip address 192.168.1.50 255.255.255.0
 no shutdown
!
exit

You should now be able to see the IP address running show ip interface brief.

Exactly the same applies for IPv6, but you need to replace ip address 192.168.1.50 255.255.255.0 with ipv6 address 2001::1:2::50/64.

You can even configure both and have a Dual-stack interface, meaning have a "Router" (aka Layer 3) interface with IPv4 and IPv6 address simultaneously.

On the Linux host just configure an IP on the same segment than the Router like 192.168.1.52 or 2001::1:2::52. You can substitute 52 for any value you want within the range.

If you were to have a DHCP Server on the network segment (to assign an ip address automatically), the Router can be configure to obtain an IP address automatically using the ip address dhcp command instead of ip address 192.168.1.50 255.255.255.0

I hope this helps.

[chanlim]

Thank you very much.
Now I can access both devices.