arp problems with 2.1.21

Richard Gooch (rgooch@atnf.CSIRO.AU)
Thu, 16 Jan 1997 12:45:25 +1100

Hi, all. I find that I can't manually set up an ARP cache entry with
linux 2.1.21 (worked fine with 2.0.x). If I do:

# arp -v -i eth1 -s <ipaddr> <hw_addr>
arp: SIOCSARP()
arp: OLD_SIOCSARP()
SIOCSARP and OLD_SIOCSARP: Invalid argument
Probably destination is on different Interface. See arp(8)

This is with the arp compiled from net-tools-1.32-alpha, with libc
5.4.17, gcc 2.7.2. It doesn't matter if my /usr/include/{linux|asm}
files are from 2.0.0 or 2.1.21, I get the same effect.
The old arp I was running (compiled from net-tools-1.3.6-BETA5, with
libc 5.3.7) gives the following:

# arp -v -i eth1 -s <ipaddr> <hw_addr>
has_mask=1
has_device=1
SIOCSARP: Invalid argument

Note that eth1 has been set up as a point-to-point interface, and
<ipaddr> has been set up in the routing table correctly. So, is this
sort of thing no longer possible? What has changed?

Regards,

Richard....