Pessoal estou fazendo alguma coisa errada na liberado dos emails:
Os clientes de emails são: outlook e outlook express ( ambos da M$)
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#Liberando email
#
iptables -A FORWARD -p udp -s 192.168.0.0/24 -d <IP_DNS_Embratel> --dport 53 -j ACCEPT
iptables -A FORWARD -p udp -s <IP_DNS_Embratel> --sport 53 -d 192.168.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -s 192.168.0.0/24 --dport 25 -j ACCEPT
iptables -A FORWARD -p tcp -s 192.168.0.0/24 --dport 110 -j ACCEPT
iptables -A FORWARD -p tcp --sport 25 -j ACCEPT
iptables -A FORWARD -p tcp --sport 110 -j ACCEPT
#iptables -A INPUT -p tcp -s <IP_Servidor_Email> --sport 25 -j ACCEPT
#iptables -A INPUT -p tcp -s <IP_Servidor_Email> --sport 110 -j ACCEPT
#iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 110 -j ACCEPT
#iptables -A FORWARD -s 192.168.0.0/24 -p tcp --sport 110 -j ACCEPT
#iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 25 -j ACCEPT
#iptables -A FORWARD -s 192.168.0.0/24 -p tcp --sport 25 -j ACCEPT
#SMTP <IP_Servidor_Email>
iptables -t nat -A PREROUTING -s 192.168.0.0/24 -p tcp --dport 25 -j DNAT --to <IP_Servidor_Email>:25
#POP <IP_Servidor_Email>
iptables -t nat -A PREROUTING -s 192.168.0.0/24 -p tcp --dport 110 -j DNAT --to <IP_Servidor_Email>:110
Obs: Meu servidor de email é externo
Configuração do meu SQUID.conf
#################################################
#################################################
#Arquivo de configuração SQUID
#Tags comuns
cache_access_log /var/log/squid/access.log
cache_log /var/log/squid/cache.log
cache_mem 256 Mb
cache_swap_log /var/spool/squid/swap.log
cache_dir diskd /var/spool/squid 1024 16 256
#Porta de Acesso
http_port 3128 transparent
#Nome da Rede
visible_hostname GANZAROLLI
#Configuração Minima do Squid
#acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
acl SSL_ports port 443 563
acl Safe_ports port 80
acl Safe_ports port 21
acl Safe_ports port 443 563
acl Safe_ports port 70
acl Safe_ports port 210
acl Safe_ports port 1025-65535
acl Safe_ports port 280
acl Safe_ports port 488
acl Safe_ports port 591
acl Safe_ports port 777
acl Safe_ports port 4226
acl CONNECT method CONNECT
#Configuração MÃnima do http_access
http_access allow manager localhost
http_access deny manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
#ACL que identifica a REDE
acl all src 192.168.0.0/24
#Bloqueio de msn
acl msnbloque url_regex -i "/etc/squid/srcmsn"
acl msnlibera src "/etc/squid/msnliberados"
http_access deny msnbloque !msnlibera
#Liberando a net na hora do almoço
#acl almoco time MTWHF 12:00-14:00
#http_access allow almoco !proibidos
http_access allow localhost
#Grupo de ips liberados
acl cpd src "/etc/squid/liberados"
http_access allow cpd
# Zona de Segurança A
acl grupo1 src "/etc/squid/grupo1.txt"
acl sites_grupo1 url_regex -i "/etc/squid/sites_grupo1"
http_access allow grupo1 sites_grupo1
#Zona de Segurança B
#acl grupo2 src "/etc/squid/grupo2"
#acl sites_grupo2 url_regex -i "/etc/squid/sites_grupo2"
#http_access allow grupo2 sites_grupo2
#Bloqueando todo o resto
http_access deny all
#http_reply
http_reply_access allow all
icp_access allow all
error_directory /usr/share/squid/errors/Portuguese
#coredump_dir /var/spool/squid