linux request time out to local interface

are you using something like xen? Have you configured the bridge correctly? I belive your VIF are natted and can't see the external network. Provide more details on system, please

im using a cisco router routing and L2 cisco switch for vlan

LAN1, Firewall, 192.168.10.0/24
LAN2, DMZ        192.168.20.0/24
LAN3                 192.168.30.0/24

like that i have 8 vlans

instead of linux firewall, if i use microsoft ISA, i dont have any time out issues
but this linux box givin time out

what are your iptables rules?

i tested this way

from PC1 192.168.50.50/24   i get time out to 192.168.10.10

at the same time i ping from PC2 192.168.20.20 to 192.168.10.10, i get time outs

meaning PC1 and PC2 does get time outs, but time varies
if PC1 get time outs, PC2 dont
if PC2 get time outs, PC1 doesnt

Use traceroute. Whan you get timeout request actually left your machine so it disappeared somewhere else.

192.168.50.50, gateway, 192.168.50.1

192.168.50.50 is vlan sub interface on router
192.168.50.80 is vlan on linux, (from my knowledge only way to add different network ranges to linux is by adding vlan)

if i tracert to internet, it goes to
192.168.50.1
192.168.50.80
then it goes to internet

also i found that to tracert between local network eg between 192.168.50.1 & 192.168.50.80 it slow, but when it goes to internet its fast