problem with download limit

[OpenBSD Geek]

Hi,

I meet a strange problem, at work, i have a firewall using OpenBSD 4.8
with PF enabled.
OpenBSD 4.8 with 2 network cards 10/100 MB, net.inet.ip.forwarding=1

When i try to download (with a computer in our lan) a file 001.dmg, it
downloads at a speed like 32 Ko/s (max). I tried to disable PF : 'pfctl -d'
and on the firewall download it using wget, it always downloads at 32 Ko.
So the problem isn't the pf ruleset.

Now i remove the firewall, and put a win7 Machine with the public address,
it downloads at 82 Ko/s.

I don't understand why the OpenBSD Box limit my download. 
Any idea ?

Thank you very much.

Wesley.


Here my ifconfig :
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33200
        priority: 0
        groups: lo
        inet 127.0.0.1 netmask 0xff000000
        inet6 ::1 prefixlen 128
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x4
rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        lladdr 00:50:fc:47:05:00
        priority: 0
        media: Ethernet autoselect (100baseTX full-duplex)
        status: active
        inet 192.168.0.2 netmask 0xffffff00 broadcast 192.168.0.255
        inet6 fe80::250:fcff:fe47:500%rl0 prefixlen 64 scopeid 0x1
rl1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        lladdr 00:e0:4c:ab:34:96
        priority: 0
        groups: egress
        media: Ethernet autoselect (100baseTX full-duplex)
        status: active
        inet #public_ip#
        inet6 fe80::2e0:4cff:feab:3496%rl1 prefixlen 64 scopeid 0x2
enc0: flags=0<> mtu 1536
        priority: 0
pflog0: flags=141<UP,RUNNING,PROMISC> mtu 33200
        priority: 0
        groups: pflog