Why ue0 do ARP on non local address when using static route?

[Jin Guojun]

/etc/ethers does not help because there is no way resolve the IP by QFHN in 
ethers.

The correct way is to use router IP (10.234.37.1) between 10.234.37.0 and 
10.227.148.0 instead of interface IP (10.234.37.80) for static route.




________________________________
From: Chuck Swiger <cswiger at mac.com>
To: Jin Guojun <jguojun at sbcglobal.net>
Cc: questions freebsd <questions at freebsd.org>
Sent: Wed, February 13, 2013 12:55:07 PM
Subject: Re: Why ue0 do ARP on non local address when using static route?

On Feb 13, 2013, at 12:35 PM, Jin Guojun wrote:
> When attached a Trendent TU2-ET100 USB Ether dongle for a second interface, it 

> has no problem to talk to the local network (10.234.37.0/24), but it has 
>problem 
>
> to talk to a remote network or host (10.227.148.0/24) via eu0 interface.
> When a remote host ping this host or this host ping that remote host, ARP 
> request is always showing up.
> A static route is set and remote host is no part of the local sub net, why ARP 

> is going on?

You've told the interface that it can reach 10.227.148.52 via 10.234.37.80, 
which is
the IP ue0 was configured to use.  It sends ARPOP_REQUESTS to get the MAC 
address of
10.227.148.52 which is expected to be reachable.

> Is any sysctl parameter can fix this problem?

You can do things like use proxy-arp, or setup /etc/ethers, or NAT, or even 
configure
ue0 to be on the same subnet as 10.227.148.52 instead, perhaps using an alias.

Regards,
-- 
-Chuck