09-16-2019
What happens when you look at the arp tables, before and after?
On ethernet, as you know, the actual LAN routing is done by MAC address; so when we change IP address, we need to flush / rebuild the arp table (on both ends), generally speaking.
If we change an IP address and do not flush the arp table, there will often be an incorrect IP address <---> MAC address in the arp table and this can cause LAN routing snafus.
PS: I'm writing this based on knowledge from decades ago, off the top of my head, and have not done any research on arp in a long time.
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https://www.unix.com/unix-for-dummies-questions-and-answers/246504-solaris-11-2nd-nic-different-subnet.html
apologies if linking is not appropriate
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ARP(8C) ARP(8C)
NAME
arp - address resolution display and control
SYNOPSIS
arp hostname
arp -a [ vmunix ] [ kmem ]
arp -d hostname
arp -s hostname ether_addr [ temp ] [ pub ] [ trail ]
arp -f filename
DESCRIPTION
The arp program displays and modifies the Internet-to-Ethernet address translation tables used by the address resolution protocol
(arp(4p)).
With no flags, the program displays the current ARP entry for hostname. The host may be specified by name or by number, using Internet dot
notation. With the -a flag, the program displays all of the current ARP entries by reading the table from the file kmem (default
/dev/kmem) based on the kernel file vmunix (default /vmunix).
With the -d flag, a super-user may delete an entry for the host called hostname.
The -s flag is given to create an ARP entry for the host called hostname with the Ethernet address ether_addr. The Ethernet address is
given as six hex bytes separated by colons. The entry will be permanent unless the word temp is given in the command. If the word pub is
given, the entry will be "published"; i.e., this system will act as an ARP server, responding to requests for hostname even though the host
address is not its own. The word trail indicates that trailer encapsulations may be sent to this host.
The -f flag causes the file filename to be read and multiple entries to be set in the ARP tables. Entries in the file should be of the
form
hostname ether_addr [ temp ] [ pub ] [ trail ]
with argument meanings as given above.
SEE ALSO
inet(3N), arp(4P), ifconfig(8C)
4.3 Berkeley Distribution May 20, 1986 ARP(8C)