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Cisco PIX 515 traffic between networks

Posted on 2006-04-06
Medium Priority
Last Modified: 2013-11-16
I have a PIX 515E w/ 6 interfaces...

Outside - - Security0 - Internet
Inside - - Security100 - Network Management systems
dmz - - Security10 - Web, DNS, Proxy, SMTP servers (inbound & outbound)
corporate - - Security80 - Our internal corporate network

I have 6 IPs I can use on my external interface.

I need my management & monitoring systems on the Inside interface to access all the hosts on the dmz & corporate interfaces, plus some external systems on the Internet.

I need the systems on my Corporate network to access the systems on the DMZ network.

All the networks need access to the Internet.

I've tried working with NAT 0 and can't seem to get it to work they way I want.

This is a stripped version of my config (I've removed all the existing NAT entries, since right now they're only for some VPNs we have).

interface ethernet0 100full
interface ethernet1 100full
interface ethernet2 100full
interface ethernet3 100full
interface ethernet4 100full
interface ethernet5 auto shutdown
nameif ethernet0 outside security0
nameif ethernet1 inside security100
nameif ethernet2 dmz security10
nameif ethernet3 corporate security80
nameif ethernet4 intf4 security1
nameif ethernet5 intf5 security1
clock timezone EST -5
clock summer-time EDT recurring
fixup protocol dns maximum-length 512
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol pptp 1723
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol sip 5060
fixup protocol sip udp 5060
fixup protocol skinny 2000
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
access-list FromInet permit tcp any host eq smtp
access-list FromInet permit tcp any host eq https
access-list FromInet permit tcp any host eq www
access-list FromInet permit udp any host eq domain
access-list FromInet permit tcp any host eq ftp
access-list FromInet permit udp any host eq domain
access-list FromInet permit tcp any host eq pop3
access-list FromInet permit tcp any host eq smtp
pager lines 24
mtu outside 1500
mtu inside 1500
mtu dmz 1500
mtu corporate 1500
mtu intf4 1500
mtu intf5 1500
ip address outside
ip address inside
ip address dmz
ip address corporate
no ip address intf4
no ip address intf5
ip verify reverse-path interface outside
ip verify reverse-path interface inside
ip verify reverse-path interface dmz
ip verify reverse-path interface corporate
ip audit info action alarm
ip audit attack action alarm
no failover
failover timeout 0:00:00
failover poll 15
no failover ip address outside
no failover ip address inside
no failover ip address dmz
no failover ip address ets
no failover ip address itservices
no failover ip address intf5
no pdm history enable
arp timeout 14400
global (outside) 10 interface
nat (inside) 10 0 0
nat (dmz) 10 0 0
nat (corporate) 10 0 0
static (dmz,outside) tcp www www netmask 0 0
static (dmz,outside) udp domain domain netmask 0 0
static (dmz,outside) tcp ftp ftp netmask 0 0
static (dmz,outside) tcp 3128 3128 netmask 0 0
static (dmz,outside) tcp pop3 pop3 netmask 0 0
static (dmz,outside) tcp smtp smtp netmask 0 0
static (dmz,outside) udp domain domain netmask 0 0
static (dmz,outside) tcp smtp smtp netmask 0 0
static (inside,outside) tcp https https netmask 0 0
static (outside,dmz) dns netmask 0 0
static (outside,dmz) dns netmask 0 0
static (outside,inside) dns netmask 0 0
static (outside,inside) dns netmask 0 0
access-group FromInet in interface outside
route outside 1
timeout xlate 0:05:00
timeout conn 10:00:00 half-closed 0:05:00 udp 1:00:00 rpc 0:10:00 h225 1:00:00
timeout h323 0:05:00 mgcp 0:05:00 sip 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server TACACS+ max-failed-attempts 3
aaa-server TACACS+ deadtime 10
aaa-server RADIUS protocol radius
aaa-server RADIUS max-failed-attempts 3
aaa-server RADIUS deadtime 10
aaa-server LOCAL protocol local
snmp-server host itservices netmgmt
snmp-server location STESI Server Room
snmp-server contact admin@sttenergy.com
snmp-server community stesi
no snmp-server enable traps
floodguard enable

Currently, hosts on the Internet can access the hosts on the DMZ network without a problem using NAT & statics.

All of the networks can access the Internet without problems.  I cannot seem to get traffic to move between the networks.
Question by:shawnsouthern
  • 2
LVL 20

Expert Comment

ID: 16391667
 Without seeing the rest of your config (particularly any nat entries):
As long as you're not *initiating* traffic from the less-trusted interfaces (such as DMZ or corporate) to the inside interface, you won't need to apply ACLs to the DMZ or corporate interfaces, so do the following:

clear xlate
static (dmz,inside) netmask
static (corporate,inside) netmask

This disables NAT between DMZ/inside, & corporate/inside, so as long as you initiate a connection from the inside, you can access the DMZ hosts by their actual IPs (10.2.2.x), for example.


Author Comment

ID: 16400816
The issue actually appears to be with these entries:

static (outside,dmz) dns netmask 0 0
static (outside,dmz) dns netmask 0 0
static (outside,inside) dns netmask 0 0
static (outside,inside) dns netmask 0 0

I need to have some sort of DNS/alias working to access the web sites in the DMZ from internal, since I really don't want to have to maintain 2 sets of DNS servers just for that to work.

If I remove those entries, traffic flows, but I lose the DNS aliasing that I need.
LVL 20

Accepted Solution

calvinetter earned 1000 total points
ID: 16407738
 You've got several unnecessary/incorrect static entries.  When doing "DNS doctoring" you also need to add the "dns" keyword on your nat (<interface>) statements.
  Try this:
clear xlate
clear local
no static (dmz,outside) tcp www www
no static (dmz,outside) udp domain domain
no static (dmz,outside) tcp ftp ftp
no static (dmz,outside) tcp 3128 3128
no static (dmz,outside) tcp pop3 pop3
no static (dmz,outside) tcp smtp smtp
no static (dmz,outside) udp domain domain
no static (outside,dmz) dns
no static (outside,dmz) dns
no static (outside,inside) dns
no static (outside,inside) dns
no nat (inside) 10
no nat (dmz) 10
no nat (corporate) 10
nat (inside) 10 dns
nat (dmz) 10 dns
nat (corporate) 10 dns
static (dmz,outside) dns
static (dmz,outside) dns


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