NetBSD vs Microsoft NLB

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

Microsoft Network Load Balancing is similar to carp(4). You have a shared 
address which is handled by multiple hosts. Whenever there isn't an ARP 
entry you get an error when connecting to the shared address with ftp(1). 
ping and telnet seem OK. However, this isn't an ftp(1) problem as I also 
see problems when using Linux binaries that do a one-shot http fetch. 
Problem happens on NetBSD-5 and -7.

1# arp -d 10.0.0.115
arp: delete: can't locate 10.0.0.115
2# ftp -o /dev/null http://10.0.0.115/
Requesting http://10.0.0.115/
ftp: Receiving HTTP reply: Error encountered
3# ftp -o /dev/null http://10.0.0.115/
Requesting http://10.0.0.115/
100% |*********************************| 54978 70.94 MiB/s 00:00 ETA
54978 bytes retrieved in 00:00 (63.86 MiB/s)
4# arp -d 10.0.0.115
5# ftp -o /dev/null http://10.0.0.115/
Requesting http://10.0.0.115/
ftp: Receiving HTTP reply: Error encountered
6# ftp -o /dev/null http://10.0.0.115/
Requesting http://10.0.0.115/
100% |*********************************| 54978 70.94 MiB/s 00:00 ETA
54978 bytes retrieved in 00:00 (63.86 MiB/s)
7# arp -d 10.0.0.115

ping seems fine:

8# ping 10.0.0.115
PING sf (10.0.0.115): 56 data bytes
64 bytes from 10.0.0.115: icmp_seq=0 ttl=128 time=0.995530 ms
64 bytes from 10.0.0.115: icmp_seq=1 ttl=128 time=0.788178 ms
64 bytes from 10.0.0.115: icmp_seq=2 ttl=128 time=0.504927 ms
^C
----sf PING Statistics----
3 packets transmitted, 3 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.504927/0.762878/0.995530/0.246278 ms

as does telnet:
9# arp -d 10.0.0.115
10# telnet 10.0.0.115 80
Trying 10.0.0.115...
Connected to sf.
Escape character is '^]'.

Connection closed by foreign host.

--
Stephen