partial web access

I have just installed 11.0 on a machine in a subnet. Static IP # and DNS but avahi was taken down anyway as was the firewall. The subnet has machines with Windows 2000/XP, Irix,SuSe 8.4/9.2/10.1 which access the web world with no difficulty. However the 11.0 is selective:
The local (within the subnet)webserver:ok
Two external unrealated sites:ok
Sites whose target is a PDF:ok
The rest:not ok
Tcpdump shows that there is a handshake and then a timeout:
mysite.port# → external.http S
external.http → mysite.port# S
mysite.port# → external.http . ack 1
mysite.port# → external.http P 1:389
external.http → mysite.port# . ack 389

 Hope someone has been here before me,
                                       Jim