Most recent kernel where this bug did not occur: 2.6.15.7

Distribution: slackware 11

Hardware Environment: Ethernet controller: Broadcom Corporation NetXtreme
BCM5751F Fast Ethernet PCI Express (rev 21)

Software Environment: firefox 1.5.0.7 - lynx 2.8.5rel.5 - squid 2.5.STABLE12p1
on a OpenBSD 3.9 box (the client doesn't matter)

Problem Description: strange malfuncition trying to connect to a http proxy
(squid) for normal navigation, problems browsing local http server
the client hangs and doesn't get anything, here a couple of example:
---
client:
leos@NetWalker:~$ telnet 10.0.10.1 80
Trying 10.0.10.1...
Connected to 10.0.10.1.
Escape character is '^]'.
GET

proxy server:
# tail -f /var/www/logs/access.log
192.168.1.2 - - [26/Oct/2006:15:40:41 +0200] "GET" 200 1320


client:
leos@NetWalker:~$ lynx www.pippo.com 
HTTP request sent; waiting for response.

proxy server:
# tail -f /var/squid/logs/access.log|grep 192.168.1.2
1161870222.546      5 192.168.1.2 TCP_MEM_HIT/200 3314 GET
http://www.pippo.com/ - NONE/- text/html
---

Steps to reproduce: kernel >= 2.6.16 - try to navigate using squid proxy