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New Member

proper usage of the arp cmd on old 1602R

We have a problem where our replacement firewall is showing the MAC address on a 'show arp' command still show as "Incomplete". I've tried changing the main switch the network goes into with no luck.

I can't seem to get the syntax correct on the arp command. Seeing if anyone here might. Here are some results from my session:

show arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 192.168.1.22 0 0008.a109.4021 ARPA Ethernet0

Internet 192.168.1.254 0 Incomplete ARPA

-----------------------------

config

Configuring from terminal, memory, or network [terminal]? terminal

Enter configuration commands, one per line. End with CNTL/Z.

arp 192.168.1.1 0090.7F1A.0179 e0

% Invalid input detected at '^' marker.

-----------------------------

arp 192.168.1.1 0090.7F1A.0179 Ethernet0

^

% Invalid input detected at '^' marker.

-----------------------------

(config)#arp Ethernet0 192.168.1.1 0090.7F1A.0179

% Invalid input detected at '^' marker.

-----------------------------

arp e0 192.168.1.1 0090.7F1A.0179

^

% Invalid input detected at '^' marker.

-----------------------------

Now here I at least do not get an error:

arp 192.168.1.254 0090.7F1A.0177 arpa

Internet 192.168.1.254 - 0090.7f1a.0177 ARPA

-----------------------------

WHen I run 'show arp':

Internet 192.168.1.254 - 0090.7f1a.0177 ARPA

Notice the Interface field is blank!

-----------------------------

Here's what happens when I try to add the interface:

arp 192.168.1.254 0090.7F1A.0177 arpa Ethernet0

Bad ARP command - Interface may only be specified when bridging IP

---------------

Anyone see what I'm doing wrong? I am using these 2 Cisco reference pages, both which have slight variations on the 'arp' command syntax:

http://www.cisco.com/en/US/products/hw/contnetw/ps792/products_configuration_guide_chapter09186a00801ee712.html

http://www.cisco.com/en/US/products/ps5763/products_command_reference_chapter09186a008029ec65.html

2 REPLIES
Silver

Re: proper usage of the arp cmd on old 1602R

Can you make the Arp Timeout value to non-zero on ALL interfaces, do a clear arp cache, and send me another show Arp. MAC addresses of 00c0 indicate Cisco devices.

"""ARP TIMEOUT

To configure how long an entry remains in the ARP cache, use the arp timeout interface configuration command. To restore the default value, use the no form of this command.

arp timeout seconds

no arp timeout seconds

This command is ignored when issued on interfaces that do not use ARP. The show interfaces EXEC command displays the ARP timeout value.

New Member

Re: proper usage of the arp cmd on old 1602R

Well the local machines and the router show, but not the replacement firewall:

# show arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 192.168.1.1 - 0002.b91d.8615 ARPA Ethernet0

What else can we try?

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