My Linksys EtherFast 10/100 Integrated PC Card (Model No: PCM100) is
detected and configured (using 1.6 i386 on a Toshiba Tecra 740CDT). (I
think I tried -current too.)

ne2 at pcmcia1 function 0 port 0x400-0x40f port 0x410-0x41f
ne2: Linksys Combo EthernetCard Ethernet
ne2: Ethernet address 01:d4:ff:03:00:20
nsphyter0 at ne2 phy 5: DP83815 10/100 media interface, rev. 3
nsphyter0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX,

UDP and ICMP traffic worked fine, but no TCP traffic back in.

23:12:47.191585 209.166.74.78.ftp > 192.168.0.14.65519: S
1340337730:1340337730(0) ack 3666850963 win 16352 <mss 1460>
23:12:51.072660 192.168.0.14.65518 > 209.166.74.78.ftp: S
1033375560:1033375560(0) win 16384 <mss 1460,nop,wscale
0,nop,nop,timestamp 0 0>
23:12:51.072710 192.168.0.14.65518 > 209.166.74.78.ftp: S
1033375560:1033375560(0) win 16384 <mss 1460,nop,wscale
0,nop,nop,timestamp 0 0>
23:12:51.131811 209.166.74.78.ftp > 192.168.0.14.65518: S
881252935:881252935(0) ack 1033375561 win 16352 <mss 1460>
23:12:54.139253 209.166.74.78.ftp > 192.168.0.14.65518: S
881252935:881252935(0) ack 1033375561 win 16352 <mss 1460>

I noticed a posting from Kyle McMartin from last January about same
issue.
http://mail-index.netbsd.org/netbsd-help/2002/01/25/0003.html
http://mail-index.netbsd.org/netbsd-help/2002/01/25/0006.html

Kyle, did you send-pr this?

Before I start comparing OpenBSD code for this, has anyone looked at this?

   Jeremy C. Reed
   http://bsd.reedmedia.net/