Configurar placas de rede em servidor Centos 7

GeisonRDS · 21 de maio de 2018

Boa noite galera, precisei criar um servidor proxy utilizando um notebook Acer que é a única máquina disponível que possuo e estou com dificuldades em acesso a internet com os clientes wifi. O notebook é um Acer com 3gb de ram, processador core i3, 240gb de disco, placa de rede ethernet e uma placa de rede wifi usb.

A minha ideia era criar um servidor proxy que distribuiria a internet pela placa wifi usb, então instalei o Centos 7 conectei o cado do modem da mina operadora de internet no notebook e pluguei a placa wifi usb.

A placa ethernet que está plugada no modem da operadora ficou assim:

placa enp2s0f0

IP 192.168.2.1

A placa wifi usb configurei como access pint e ficou assim:

IP 192.168.1.1

Gateway 192.168.2.1

DNS 8.8.8.8

DNS 8.8.4.4

Depois de configurar as placas de rede instalei o squid, o dhcp e configurei o iptables, consigo conectar na rede wifi mas não tenho acesso a internet já fiz várias alterações no squid.conf, no script do iptables e não consigo acessar a internet, não tenho experiência em redes e acredito que possa ter cometido algum erro, já pesquisei em vários foruns e blogs e não consegui resolver o problema, abaixo está o script do firewall iptables e os arquivos de configuração do squid e do dhcp.

Agradeço a ajuda.

firewall iptables

#!/bin/bash

iniciar_firewall(){
echo "################################################"
echo "# SCRIPT FIREWALL - COMPARTILHAMENTO DE REDE   #"                                            
echo "################################################"

externa="enp2s0f0"
interna="wlp0s29u1u2"
rede_interna="192.168.1.0/24"

echo "Interface Rede Externa .......................... "$externa
echo "Interface Rede Interna .......................... "$interna
echo "Faixa de IP Rede Interna ........................ "$rede_interna

echo "Limpando Politicas .............................. [ OK ]" 
iptables -X
iptables -Z
iptables -F INPUT
iptables -F OUTPUT
iptables -F FORWARD
iptables -F -t nat
iptables -F -t filter
iptables -F -t mangle

echo "Aplicando nova politica ......................... [ OK ]"
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP

echo "Ativa Modulos Basicos ........................... [ OK ]"
modprobe ip_tables
modprobe ip_conntrack
modprobe iptable_filter
modprobe iptable_mangle
modprobe iptable_nat
modprobe ipt_LOG
modprobe ipt_limit
modprobe ipt_state
modprobe ipt_REDIRECT
modprobe ipt_owner
modprobe ipt_REJECT
modprobe ipt_MASQUERADE
modprobe ip_conntrack_ftp
modprobe ip_nat_ftp

echo "Roteamento de Kernal ............................ [ OK ]"
echo 1 > /proc/sys/net/ipv4/ip_forward

echo "Compartilhar Internet ........................... [ OK ]"
iptables -t nat -A POSTROUTING -o $externa -j MASQUERADE

echo "Mantendo conexões estabelecidas ................. [ OK ]"
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED,NEW -j ACCEPT
iptables -A OUTPUT -m state --state RELATED,ESTABLISHED,NEW -j ACCEPT

echo "Logs de bloqueios ............................... [ OK ]"
iptables -A INPUT -j LOG
iptables -A OUTPUT -j LOG
iptables -A FORWARD -j LOG

echo "Regras DNAT para servidor WEB ................... [ OK ]"
iptables -t nat -A PREROUTING -i $externa -p tcp --dport 80 -j DNAT --to 192.168.1.1:80

#REGRAS FORWARD
echo "Permite ping pra Rede Externa ................... [ OK ]"
iptables -A FORWARD -i $interna -o $externa -p icmp -j ACCEPT

echo "Permite conexões da Rede Interna pra Externa .... [ OK ]"
iptables -A FORWARD -i $interna -o $externa -p tcp -m multiport --dports 80,443,3128,110,20,21,587,995,143,22,3389,25,5900,5100,3389 -j ACCEPT

echo "Regras cliente .................................. [ OK ]"
iptables -A OUTPUT -p tcp -m multiport --dports 80,443 -j ACCEPT
iptables -A OUTPUT -p udp --dport 53 -j ACCEPT


echo "Regras servidor ................................. [ OK ]"
iptables -A INPUT -p tcp -i $interna --dport 22 -j ACCEPT
iptables -A INPUT -p tcp -i $interna -m multiport --dports 3128,443,445,113,80,587,25,22,110,53,139,5900,5100,3389 -j ACCEPT
iptables -A INPUT -p udp -i $interna -m multiport --dports 53,110,67,68,137,113,443,138 -j ACCEPT 

echo "Redirecionamento de porta ....................... [ OK ]"
iptables -t nat -A PREROUTING -i $interna -p tcp --dport 80 -j REDIRECT --to-port 3128 

echo "Permite conexões loopback ....................... [ OK ]"
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

echo "##################### SEGURANÇA ########################"

echo "Segurança contra IP Spoofing .................... [ OK ]"
echo 1 > /proc/sys/net/ipv4/conf/default/rp_filter
iptables -A INPUT -m state --state INVALID -j DROP

echo "Proteção contra alteração de rota ............... [ OK ]"
echo 0 > /proc/sys/net/ipv4/conf/all/accept_redirects

echo "Proteção contra alteração de caminho ............ [ OK ]"
echo 0 > /proc/sys/net/ipv4/conf/all/accept_source_route

echo "Proteção contra responses bogus ................. [ OK ]"
echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses

echo "Bloqueando traceroute ........................... [ OK ]"
iptables -A INPUT -p udp -s 0/0 -i $interna --dport 33435:33525 -j DROP

echo "Proteção para SYN flood ......................... [ OK ]"
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
iptables -A FORWARD -p tcp --syn -m limit --limit 1/s -j ACCEPT
iptables -A FORWARD -p tcp --syn -j DROP

echo "Negando portas invalidas (trojans, trinoo) ...... [ OK ]"
iptables -A INPUT -p tcp -i $externa -m multiport --dports 666,4000,6000,6006,16660,27444,27665,31335,34555,35555 -j DROP
iptables -A INPUT -p tcp -i $interna -m multiport --dports 1433,6670,6711,6712,6713,12345,12346,20034,31337,6000 -j DROP

echo "Proteção contra telnet .......................... [ OK ]"
iptables -A INPUT -p TCP -i $externa --dport telnet -j DROP

echo "Dropando pacotes TCP indesejaveis ............... [ OK ]"
iptables -A FORWARD -p tcp ! --syn -m state --state NEW -j DROP

echo "Proteção contra worms ........................... [ OK ]"
iptables -A FORWARD -p tcp --dport 135 -i $externa -j REJECT

echo "Proteção contra ICMP Broadcasting ............... [ OK ]"
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

echo "Proteção contra Port Scanners ocultos ........... [ OK ]"
iptables -A INPUT -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 1/s -j ACCEPT
iptables -A FORWARD -p tcp --tcp-flags SYN,ACK,FIN,RST RST -m limit --limit 1/s -j ACCEPT

echo "Proteção contra Ping da morte ................... [ OK ]"
iptables -A FORWARD -p icmp --icmp-type echo-request -m limit --limit 1/s -j ACCEPT

echo "Proteção contra IP Spoofing ..................... [ OK ]"
iptables -A INPUT -s 172.16.0.0/12 -i $externa -j DROP
iptables -A INPUT -s 127.0.0.0/8 -i $externa -j DROP
iptables -A INPUT -s 10.0.0.0/8 -i $externa -j DROP
iptables -A INPUT -s 192.168.0.0/16 -i $externa -j DROP

echo "Bloqueando Pacotes Fragmentados.................. [ OK ]"
iptables -A INPUT -i $externa -f -j LOG --log-prefix "Pacote Fragmentado: "
iptables -A INPUT -i $externa -f -j DROP
iptables -A INPUT -i $interna -f -j LOG --log-prefix "Pacote Fragmentado: "
iptables -A INPUT -i $interna -f -j DROP

}
parar_firewall(){

echo "Parando Firewall ................................ [ OK ]"
iptables -X
iptables -F 
iptables -t nat -F
iptables -t filter -F
iptables -t mangle -F

echo "Liberando Politicas ............................. [ OK ]"
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

echo "Parando  ................................ [ OK ]"
echo 0 > /proc/sys/net/ipv4/ip_forward

echo "Firewall Desativado............................. [ OK ]"
}

case "$1" in
"start") iniciar_firewall ;;
"stop") parar_firewall ;;
"restart") parar_firewall; iniciar_firewall;;
*) echo "Use os parametros | start | stop | restart |"
esac

squid.conf


#
# Recommended minimum configuration:
#

# Example rule allowing access from your local networks.
# Adapt to list your (internal) IP networks from where browsing
# should be allowed
acl localnet src 10.0.0.0/8     # RFC1918 possible internal network
acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
acl localnet src fc00::/7	# RFC 4193 local private network range
acl localnet src fe80::/10	# RFC 4291 link-local (directly plugged) machines

acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT

#
# Recommended minimum Access Permission configuration:
#
# Deny requests to certain unsafe ports
#http_access deny !Safe_ports

# Deny CONNECT to other than secure SSL ports
http_access deny CONNECT !SSL_ports

# Only allow cachemgr access from localhost
http_access allow localhost manager

# We strongly recommend the following be uncommented to protect innocent
# web applications running on the proxy server who think the only
# one who can access services on "localhost" is a local user
#http_access deny to_localhost

#
# INSERT YOUR OWN RULE(S) HERE TO ALLOW ACCESS FROM YOUR CLIENTS
#

# Example rule allowing access from your local networks.
# Adapt localnet in the ACL section to list your (internal) IP networks
# from where browsing should be allowed
http_access allow localnet
http_access allow localhost

# And finally deny all other access to this proxy
http_access deny all

# Squid normally listens to port 3128
http_port 3128 transparent

# Uncomment and adjust the following to add a disk cache directory.
#cache_dir ufs /var/spool/squid 100 16 256

# Leave coredumps in the first cache dir
coredump_dir /var/spool/squid

#
# Add any of your own refresh_pattern entries above these.
#
refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%	1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%	0
refresh_pattern .               0	20%     4320

dhcpd.conf


#
# DHCP Server Configuration file.
#   see /usr/share/doc/dhcp*/dhcpd.conf.example
#   see dhcpd.conf(5) man page
#

####Our basic DHCP example configuration

####Our Domain
option domain-name "fpv.local";

####The DNS servers for name resolution
option domain-name-servers 8.8.8.8;

####Our IP Lease time
default-lease-time 600;
max-lease-time 7200;

####Use this to enble / disable dynamic dns updates globally.
ddns-update-style none;

#### This DHCP server is the official DHCP server for the local network.
authoritative;

#### Use this to send dhcp log messages to a different log file (you also

#### have to hack syslog.conf to complete the redirection).
log-facility local7;

#### Our Subnet, IP address Pool and gateway/router
subnet 192.168.1.0 netmask 255.255.255.0 {
 range dynamic-bootp 192.168.1.10 192.168.1.253;
 option broadcast-address 192.168.1.255;
 option routers 192.168.1.254;
}

#### Use this to send dhcp log messages to a different log file (you also

#### have to hack syslog.conf to complete the redirection).
log-facility local7;

#### Our Subnet, IP address Pool and gateway/router
subnet 192.168.1.0 netmask 255.255.255.0 {
 range dynamic-bootp 192.168.1.10 192.168.1.253;
 option broadcast-address 192.168.1.255;
 option routers 192.168.1.254;
}