Hola amigos les comento que implementamos un proxy en centos 5.4 el cuál funciona perfectamente el problema se da cuando los usuarios que poseen computadoras mac desean usar el outlook... Sale no hay conexion con el servidor intentamos habilitar los puertos pero igual no funciona..


# generated by iptables-save v1.3.5 on wed mar 20 19:24:03 2013

*nat
:
prerouting accept [944:58580]
:
postrouting accept [530:34340]
:
output accept [535:39564]


-a prerouting -p tcp -m multiport --dports 80,110,25,995 -j redirect --to-ports 3128

-a prerouting -p tcp -m multiport --dports 80,995,25,110,465,993,443,53 -j redirect --to-ports 3128

-a prerouting -p tcp -m multiport --dports 143 -j redirect --to-ports 3128

-a postrouting -s 192.168.1.0/255.255.255.0 -o eth1 -j masquerade

-a postrouting -s 192.168.1.0/255.255.255.0 -o eth1 -p tcp -m tcp --dport 995 -j masquerade

-a postrouting -s 192.168.1.0/255.255.255.0 -o eth1 -p tcp -m tcp --dport 993 -j masquerade

-a postrouting -s 192.168.1.0/255.255.255.0 -o eth1 -p tcp -m tcp --dport 25 -j masquerade

-a postrouting -s 192.168.1.0/255.255.255.0 -o eth1 -p tcp -m tcp --dport 110 -j masquerade


commit


# completed on wed mar 20 19:24:03 2013

# generated by iptables-save v1.3.5 on wed mar 20 19:24:03 2013

*filter
:
input accept [82828:119344868]
:
forward accept [0:0]
:
output accept [160708:125701316]

-a input -s 192.168.1.0/255.255.255.0 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 110 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 995 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 25 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 993 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 465 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 80 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 443 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 53 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p udp -m udp --dport 53 -j accept

-a forward -s 192.168.1.0/255.255.255.0 -i eth1 -p tcp -m tcp --dport 143 -j accept

commit

# completed on wed mar 20 19:24:03 2013

seria fabuloso q me ayudaran gracias