DHCP oddity

Skylar Thompson skylar at cs.earlham.edu
Tue Dec 27 08:43:17 PST 2005


Brian Candler wrote:

>On Mon, Dec 26, 2005 at 12:15:14PM -0600, Skylar Thompson wrote:
>  
>
>>While doing some network stress-tests from a dual-CPU x86 FreeBSD 5.4 
>>server, I noticed that a "ping -f" drives dhcpd's CPU usage way up. I 
>>put dhcpd into debug mode and didn't  get any error messages. I then ran 
>>dhcpd with strace, and saw loads of these messages when I started the 
>>ping flood:
>>
>>select(8, [?], [?], [?], NULL)          = 1 ()
>>gettimeofday({...}, NULL)               = 0
>>recvfrom(4, 0xbfbfe090, 1500, 0, {...}, [?]) = 84
>>select(8, [?], [?], [?], NULL)          = 1 ()
>>gettimeofday({...}, NULL)               = 0
>>recvfrom(4, 0xbfbfe090, 1500, 0, {...}, [?]) = 84
>>
>>Does anyone know why this would happen?
>>    
>>
>
>Were you running tcpdump or similar at the same time, such that the
>interface was put into promiscuous mode?
>
>Check using ifconfig that it is not (i.e. there is no PROMISC flag shown)
>_______________________________________________
>  
>

No. Here's the setup of the NIC:

bge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=1a<TXCSUM,VLAN_MTU,VLAN_HWTAGGING>
        inet 159.28.234.1 netmask 0xffffff00 broadcast 159.28.234.255
        inet6 fe80::210:18ff:fe11:ea1f%bge0 prefixlen 64 scopeid 0x1
        ether 00:10:18:11:ea:1f
        media: Ethernet autoselect (1000baseTX <full-duplex>)
        status: active

I've also tried this using the on-board 100Mbps fxp adapter, and I get 
the same results.

-- 
-- Skylar Thompson (skylar at cs.earlham.edu)
-- http://www.cs.earlham.edu/~skylar/

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 256 bytes
Desc: OpenPGP digital signature
Url : http://lists.freebsd.org/pipermail/freebsd-net/attachments/20051227/3fccf0cc/signature.bin


More information about the freebsd-net mailing list