04-03-2003 07:07 AM - edited 02-20-2020 10:40 PM
I work for a local ISP and am putting in a PIX firewall for the first time. It is going to go between the router on our backbone and a PC setup as a router. We got a small hub and my plan is to have the Ethernet address on the backbone router changed to 10.10.10.1 and then the outside interface on the PIX to 10.10.10.2 and plug those into the hub. The inside interface will go to our LAN in the office. The router in the office has an IP address of 192.168.1.5, but actually has a real IP but kept out for security reasons. (as well as the inside interface on the PIX) I am having a hard time understanding exactly how the PIX routes, we tried it with the configuration that is shown and it didnt work. I am sure i have several issues wrong with the config. Any help would be great! Thanks.
: Saved
:
PIX Version 6.1(4)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
nameif ethernet2 intf2 security10
nameif ethernet3 intf3 security15
nameif ethernet4 intf4 security20
nameif ethernet5 intf5 security25
enable password Vc5SuIC5HTy5.dBK encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname PIXFIREWALL
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 1720
fixup protocol rsh 514
fixup protocol rtsp 554
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol sip 5060
fixup protocol skinny 2000
names
pager lines 24
interface ethernet0 auto
interface ethernet1 auto
interface ethernet2 auto shutdown
interface ethernet3 auto shutdown
interface ethernet4 auto shutdown
interface ethernet5 auto shutdown
mtu outside 1500
mtu inside 1500
mtu intf2 1500
mtu intf3 1500
mtu intf4 1500
mtu intf5 1500
ip address outside 10.10.10.2 255.255.255.0
ip address inside 192.168.1.1 255.255.255.0
ip address intf2 127.0.0.1 255.255.255.255
ip address intf3 127.0.0.1 255.255.255.255
ip address intf4 127.0.0.1 255.255.255.255
ip address intf5 127.0.0.1 255.255.255.255
ip audit info action alarm
ip audit attack action alarm
no failover
failover timeout 0:00:00
failover poll 15
failover ip address outside 0.0.0.0
failover ip address inside 0.0.0.0
failover ip address intf2 0.0.0.0
failover ip address intf3 0.0.0.0
failover ip address intf4 0.0.0.0
failover ip address intf5 0.0.0.0
pdm history enable
arp timeout 14400
route inside 0.0.0.0 0.0.0.0 206.187.74.5 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h323 0:05:00 si
p 0:30:00 sip_media 0:02:00
timeout uauth 0:05:00 absolute
aaa-server TACACS+ protocol tacacs+
aaa-server RADIUS protocol radius
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
no sysopt route dnat
telnet timeout 5
ssh timeout 5
terminal width 80
Cryptochecksum:3c8e47f3297492db91ef88d9bff73d41
: end
04-03-2003 09:37 AM
I don't see any "static" or "nat" statements on the configurations above.
For traffic to pass thru the pix you need to either:
a) enable NAT.; or
b) use static ip address mapping.
Note that with NAT enabled, you can still preserve the ip address by NAT'ing an ip address to itself (it sounds crazy, but it works).
I'd suggest that you enable NAT as follows:
global (outside) 1 10.10.10.x
nat (inside) 1 192.168.1.0 255.255.255.0 0 0
this way traffic will pass thru the pix and all inside hosts will share a single "ouside" ip address of 10.10.10.x
Also you might want to point the default route to the ouside interface:
instead of
route inside 0.0.0.0 0.0.0.0 206.187.74.5 1
do:
route outside 0.0.0.0 0.0.0.0 x.x.x.x
where x.x.x.x is the your internet gateway ip address assuming that private-to-public ip address translation is done along the path.
HTH,
Mustafa
04-03-2003 09:52 AM
that inside route is supposed to say 192.168.1.5. I really dont want to have to use NAT seeing as the inside network is already done with real IP's, that would be a lot of changing.
04-03-2003 10:25 AM
You can still do that (preserve the real ip's - no translation) by using "nat 0" statement:
nat (inside) 0 192.168.1.0 255.255.255.0
static (inside, outside) 192.168.1.0 192.168.1.0 netmask 255.255.255.0
These two statements will allow 192.168.1.x hosts to establish connections to the outside thru pix (outside hosts can not establish connections to inside without proper access-lists).
Remember to use the "clear xlat" everytime you issue or modify an "static" statement (carefull: the command is disruptive to established connections).
04-03-2003 12:17 PM
There are several servers behind the PIX and people who dial-in will need to get through the pix for authentication. Would i just set up a simple access-list that i would do on a normal router?
04-03-2003 03:21 PM
The access-lists are similar to IOS routers'.
e.g: an access for inbound connections
--------------------------------------------------------------------------
access-list inbound_stuff permit tcp any host 192.168.1.5 eq ftp
access-list inbound_stuff permit tcp any host 192.168.1.6 eq www
access-list inbound_stuff permit tcp any host 192.168.1.8 eq 100
access-list inbound_stuff permit icmp any any eq echo
access-list inbound_stuff permit icmp any any eq echo-reply
access-list inbound_stuff permit ip any host 192.168.1.8
access-group inbound_stuff in interface outside
----------------------------------------------------------------------------------
The first 3 statements allow access to specific services and ports on some inside servers. Statements 4&5 allow outside hosts to ping any inside host. Statement 6 allows full access to 192.168.1.8 (no firewalling - fixup rules apply)
The last statement applies the access list to inbound connections arriving at the outside interface.
I'd recommend going thru the pix command reference:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_61/index.htm
Also, PIX version 6.2 introduced object grouping
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/pix/pix_sw/v_62/config/mngacl.htm#1024374
which - along with PDM software - greatly enhance access control configurations.
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