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Flushing the arp table

How do you flush the arp table. Do you have to do it one entry at a time, or can you just ditch the whole thing at once?

Thanks,
Bret

bhagawatula

What OS?
On HPUX and Solaris :
try route -f
to flush the table.
I think you need to add your default route again after this.

-f Flush the routing tables of all gateway entries.
If this is used in conjunction with one of the commands described above, route flushes the gate-ways before performing the command.

thacsi

arp -d hostname

You could build a wrapper script to first get all hostnames with arp -a and then remove them with arp -d.

dserna

What Unix are we talking about here? If you are interested to know on how to flush the arp table in Solaris, this is the way you would do it:

as root:

: root@ns:/export/home/dserna2: arp -a
Net to Media Table
Device IP Address Mask Flags Phys Addr
------ -------------------- --------------- ----- ---------------
le0 209.220.74.1 255.255.255.255 00:10:67:00:3f:80
le0 ns 255.255.255.255 SP 08:00:20:75:e9:29
le0 BASE-ADDRESS.MCAST.NET 240.0.0.0 SM 01:00:5e:00:00:00
: root@ns:/export/home/dserna2: ifconfig -a
lo0: flags=849<UP,LOOPBACK,RUNNING,MULTICAST> mtu 8232
inet 127.0.0.1 netmask ff000000
le0: flags=863<UP,BROADCAST,NOTRAILERS,RUNNING,MULTICAST> mtu 1500
inet 209.220.74.121 netmask ffffff00 broadcast 209.220.74.255
ether 8:0:20:75:e9:29
: root@ns:/export/home/dserna2: ifconfig le0 209.220.74.121 ; arp -a
Net to Media Table
Device IP Address Mask Flags Phys Addr
------ -------------------- --------------- ----- ---------------
le0 ns 255.255.255.255 SP 08:00:20:75:e9:29
le0 BASE-ADDRESS.MCAST.NET 240.0.0.0 SM 01:00:5e:00:00:00
: root@ns:/export/home/dserna2:

I don't know about other Unix versions. Hope that helps.

festive

regardless of what version the following could be adapted:
below should work for solaris on le0 interface

for arpent in `arp -a | grep "^le0" ` ; do
arp -d $arpent
done

you could specify multiple/all interfaces by substituting grep with egrep and using the following:
egrep "^le0|^hme0|^net0"

etc...

festive

regardless of what version the following could be adapted:
below should work for solaris on le0 interface

for arpent in `arp -a | grep "^le0" | awk ''{ print $2 }' ` ; do
arp -d $arpent
done

you could specify multiple/all interfaces by substituting grep with egrep and using the following:
egrep "^le0|^hme0|^net0"

etc...

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festive

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badreece

ASKER

That's going to work for me.
Thanks,
Bret