Solved: Nating on pix Firewall

junaid haroon · ‎05-21-2013

hi,

I have Pix firewall 515e on inside interface its has configured with IP 192.168.0.254.And Global Nating is configured.

global (outside) 1 interface

nat (inside) 1 192.168.0.0 255.255.255.0 0 0

I want i configured Global nating only for only specific IP address E.g 192.168.0.0-192.168.0.30 and 192.168.0.200-192.168.0.254

How i do this??

Jouni Forss · ‎05-21-2013

Hi,

Inbound and Outbound traffic can be controlled in the interface ACL by choosing the direction "in" or "out"

Inbound means traffic coming towards the interface

Outbound means traffic going out/heading out the interface

Here is a simple picture that should clarify this (click on the picture to enlarge)

So if you want to control traffic towards any remote network on the "inside" interface then you use an INBOUND ACL on the interface "inside". As you can see if your PC would be connecting to the Internet then the PIX would consider that INBOUND traffic on its "inside" interface.

Same goes for "outside". You control traffic coming from networks behind "outside" interface with an INBOUND ACL on the "outside" interface.

You very rarely need to use OUTBOUND ACL or atleast I have very rarely seem them being used.

Please, Remember to mark if you have found the replys to be correct answer to your question and/or rate answers using the starts at the bottom of the reply.

Hope this helps

- Jouni

View solution in original post

Jouni Forss · ‎05-21-2013

Hi,

This would be so much easier on the new firewall software

I guess you could try

global (outside) 1 interface

nat (inside) 1 192.168.0.0 255.255.255.224

nat (inside) 1 192.168.0.200 255.255.255.248

nat (inside) 1 192.168.0.208 255.255.255.248

nat (inside) 1 192.168.0.216 255.255.255.248

nat (inside) 1 192.168.0.224 255.255.255.224

Though if your objective is to block Internet traffic from the other users then I would use ACL and not configure NAT in a more complicated way

Remember to mark the reply as the correct answer if it answered your question.

Hope this helps

- Jouni

junaid haroon · ‎05-21-2013

Hi,

Can you please explain this i can't understand Its subnet is totally changed (nat (inside) 1 192.168.0.0 255.255.255.224
)

can i do it like this

nat (inside) 1 192.168.0.0-30 255.255.255.0 0 0

nat (inside) 1 192.168.0.200.254 255.255.255.0 0 0

Please tell how i configured the ACL insted of NAT complications.

Jouni Forss · ‎05-21-2013

Hi,

You CANT define a range of addresses in the NAT configuration. In the newer softwares (that your PIX doesnt support) you could do this. But thats a whole other story.

The reason I use different subnet masks is that I define the IP addresses you want to NAT

nat (inside) 1 192.168.0.0 255.255.255.224 = 192.168.0.0 - .31

nat (inside) 1 192.168.0.200 255.255.255.248 = 192.168.0.200 - .207

nat (inside) 1 192.168.0.208 255.255.255.248 = 192.168.0.208 - .215

nat (inside) 1 192.168.0.216 255.255.255.248 = 192.168.0.216 - .223

nat (inside) 1 192.168.0.224 255.255.255.224 = 192.168.0.224 - .255

- Jouni

junaid haroon · ‎05-21-2013

Hi

Thanks for explanation please tell me how i accomplish this with ACL.

Jouni Forss · ‎05-21-2013

Hi,

I guess in terms of how many lines of configurations is inserted with using either NAT or ACL to control Internet access the ACL amounts to some more.

And naturally I dont know your current configurations and ACL configurations so I can just suggest a simple one

object-group network ALLOWED-INTERNET

network-object 192.168.0.0 255.255.255.224

network-object 192.168.0.200 255.255.255.248

network-object 192.168.0.208 255.255.255.248

network-object 192.168.0.216 255.255.255.248

network-object 192.168.0.224 255.255.255.224

access-list INSIDE-IN remark Allow Internet for some users

access-list INSIDE-IN permit ip object-group ALLOWED-INTERNET any

access-list INSIDE-IN remark Deny all other users

access-list INSIDE-IN deny ip 192.168.0.0 255.255.255.0 any

access-group INSIDE-IN in interface inside

This would allow connections from the hosts/networks under the ALLOWED-INTERNET anywhere BUT it would BLOCK all others hosts traffic through the firewall

If you have some other interfaces like DMZs on the PIX then this ACL wont be the correct one and you will have to use a bit different one.

So I would suggest confirming that such an ACL doesnt break anything related to your whole setup (Since we have not seen the complete PIX configurations)

- Jouni

junaid haroon · ‎05-21-2013

Hi

Here is my firewall configuration now suggest me.

: Saved

: Written by enable_15 at 13:16:38.987 PKT Thu Apr 11 2013

PIX Version 6.3(3)

interface ethernet0 auto

interface ethernet1 auto

nameif ethernet0 outside security0

nameif ethernet1 inside security100

hostname pixfirewall

clock timezone PKT 5

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 rsh 514

fixup protocol rtsp 554

fixup protocol sip 5060

fixup protocol sip udp 5060

fixup protocol skinny 2000

no fixup protocol smtp 25

fixup protocol sqlnet 1521

fixup protocol tftp 69

names

access-list outside_int permit tcp any host 192.168.0.233 eq www

access-list outside_int permit tcp any host 192.168.0.233 eq 1024

access-list outside_int permit tcp any host 124.109.46.245 eq pop3

access-list outside_int permit tcp any host 124.109.46.245 eq www

access-list outside_int permit tcp any host 124.109.46.245 eq lotusnotes

access-list outside_int permit tcp any host 124.109.46.246 eq www

access-list outside_int permit tcp any host 124.109.46.246 eq 1532

access-list outside_int permit tcp any host 124.109.46.246 eq 1533

access-list outside_int permit tcp any host 124.109.46.248 eq ftp-data

access-list outside_int permit tcp any host 124.109.46.248 eq ftp

access-list outside_int permit tcp any host 124.109.46.248 eq 1433

access-list outside_int permit tcp any host 124.109.46.245 eq imap4

access-list outside_int permit tcp any host 124.109.46.250 eq www

access-list outside_int permit tcp any host 124.109.46.250 eq https

access-list outside_int permit tcp any host 124.109.46.246 eq lotusnotes

access-list outside_int permit tcp any host 124.109.46.246 eq smtp

access-list outside_int permit tcp any host 124.109.46.241 eq www

access-list outside_int permit tcp any host 124.109.46.249 eq 1533

access-list outside_int permit tcp any host 124.109.46.245 eq smtp

access-list outside_int permit tcp any host 124.109.46.246 eq https

access-list outside_int permit tcp any host 124.109.46.245 eq https

access-list 90 permit ip 192.168.0.0 255.255.255.0 192.168.2.0 255.255.255.0

access-list 90 permit ip 192.168.0.0 255.255.255.0 192.168.1.0 255.255.255.0

access-list 90 permit ip 192.168.0.0 255.255.255.0 192.168.10.0 255.255.255.0

access-list 90 permit ip 192.168.0.0 255.255.255.0 192.168.3.0 255.255.255.0

access-list l_map permit ip 192.168.0.0 255.255.255.0 192.168.2.0 255.255.255.0

access-list l_map permit ip host *.*.*.* 192.168.2.0 255.255.255.0

access-list p_map permit ip 192.168.0.0 255.255.255.0 192.168.3.0 255.255.255.0

access-list p_map permit ip host

*.*.*.*

192.168.3.0 255.255.255.0

access-list 101 permit ip 192.168.0.0 255.255.255.0 any

access-list k_map permit ip 192.168.0.0 255.255.255.0 192.168.1.0 255.255.255.0

access-list k_map permit ip host

*.*.*.*

192.168.1.0 255.255.255.0

pager lines 24

logging on

logging timestamp

logging trap informational

logging host inside 192.168.0.173

mtu outside 1500

mtu inside 1500

ip address outside *.*.*.* 255.255.255.240

ip address inside 192.168.0.254 255.255.255.0

ip audit info action alarm

ip audit attack action alarm

ip local pool client_pool 192.168.10.1-192.168.10.254

pdm location 124.109.46.245 255.255.255.255 outside

pdm location 124.109.46.249 255.255.255.255 outside

pdm location 192.168.0.0 255.255.255.255 inside

pdm location 192.168.0.27 255.255.255.255 inside

pdm location 192.168.0.28 255.255.255.255 inside

pdm location 192.168.0.224 255.255.255.255 inside

pdm location 192.168.0.225 255.255.255.255 inside

pdm location 192.168.0.233 255.255.255.255 inside

pdm location 192.168.1.0 255.255.255.0 outside

pdm location 192.168.2.0 255.255.255.0 outside

pdm location 192.168.3.0 255.255.255.0 outside

pdm history enable

arp timeout 14400

global (outside) 1 interface

nat (inside) 0 access-list 90

nat (inside) 1 192.168.0.0 255.255.255.0 0 0

static (inside,outside) *.*.*.* 192.168.0.224 dns netmask 255.255.255.255 0 0

static (inside,outside) *.*.*.* 192.168.0.225 dns netmask 255.255.255.255 0 0

static (inside,outside) *.*.*.* 192.168.0.28 netmask 255.255.255.255 0 0

static (inside,outside) *.*.*.* 192.168.0.27 netmask 255.255.255.255 0 0

static (inside,outside) *.*.*.* 192.168.0.16 netmask 255.255.255.255 0 0

access-group outside_int in interface outside

route outside 0.0.0.0 0.0.0.0 124.109.46.241 1

route outside 192.168.1.0 255.255.255.0 124.29.194.3 1

route outside 192.168.2.0 255.255.255.0 202.163.68.117 1

route outside 192.168.3.0 255.255.255.0 124.29.231.197 1

timeout xlate 0:15:00

timeout conn 0:20:00 half-closed 0:10:00 udp 0:02:00 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 RADIUS protocol radius

aaa-server LOCAL protocol local

http server enable

http 192.168.0.0 255.255.255.0 inside

no snmp-server location

no snmp-server contact

snmp-server community public

no snmp-server enable traps

tftp-server inside 192.168.0.173 /bk

floodguard enable

sysopt connection permit-ipsec

crypto ipsec transform-set tset esp-des esp-md5-hmac

crypto dynamic-map dmap 200 set transform-set tset

crypto map smap 6 ipsec-isakmp

crypto map smap 6 match address k_map

crypto map smap 6 set peer *.*.*.*

crypto map smap 6 set transform-set tset

crypto map smap 7 ipsec-isakmp

crypto map smap 7 match address lahore_map

crypto map smap 7 set peer *.*.*.*

crypto map smap 7 set transform-set tset

crypto map smap 8 ipsec-isakmp dynamic dmap

crypto map smap 9 ipsec-isakmp

crypto map smap 9 match address peshawar_map

crypto map smap 9 set peer *.*.*.*

crypto map smap 9 set transform-set tset

crypto map smap client configuration address respond

crypto map smap interface outside

isakmp enable outside

isakmp key ************ address *.*.*.* netmask 255.255.255.255

isakmp key ************* address *.*.*.* netmask 255.255.255.255

isakmp key ************** address 0.0.0.0 netmask 255.255.255.255

isakmp key *************** address *.*.*.* netmask 255.255.255.255

isakmp policy 10 authentication pre-share

isakmp policy 10 encryption des

isakmp policy 10 hash md5

isakmp policy 10 group 2

isakmp policy 10 lifetime 86400

vpngroup vpnclient address-pool client_pool

vpngroup vpnclient split-tunnel 90

vpngroup vpnclient idle-time 1800

vpngroup client idle-time 1800

telnet 192.168.0.0 255.255.255.255 inside

telnet 192.168.0.0 255.255.255.0 inside

telnet timeout 5

ssh timeout 5

console timeout 0

terminal width 80

Cryptochecksum:28c34496df8114513fb7f28110ed04fe

: end

Jouni Forss · ‎05-21-2013

Hi,

Seems to me that you would need the following

object-group network ALLOWED-INTERNET

network-object 192.168.0.0 255.255.255.224

network-object 192.168.0.200 255.255.255.248

network-object 192.168.0.208 255.255.255.248

network-object 192.168.0.216 255.255.255.248

network-object 192.168.0.224 255.255.255.224

access-list INSIDE-IN remark Allow traffic to remote sites

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.1.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.2.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.3.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.10.0 255.255.255.0

access-list INSIDE-IN remark Allow Internet for some users

access-list INSIDE-IN permit ip object-group ALLOWED-INTERNET any

access-list INSIDE-IN remark Deny all other users

access-list INSIDE-IN deny ip 192.168.0.0 255.255.255.0 any

access-group INSIDE-IN in interface inside

Remember to mark the reply(s) as the correct answer if they answered your question.

Hope this helps

- Jouni

junaid haroon · ‎05-21-2013

Hi

In above configuration you use access-group INSIDE-IN in interface inside where "in" mean inbound traffice.I am confused here if i am not wrong we controlling our outbound traffic.

It could be like this access-group INSIDE-IN out interface inside

Jouni Forss · ‎05-21-2013

Hi,

The direction "in" or "out" specifies the direction with regards to the interface in question.

So if we use the direction "in" here it means traffic coming towards "inside" interface and therefore heading out through the PIX.

If we used the direction "out" it would be controlling traffic/connections that were going out the interface "inside" and therefore towards the LAN network.

It goes by the same logic as your current "outside_int" ACL. You have attached it to the interface "outside" in the direction "in". Therefore it means it controls traffic coming from the network behind "outside" towards (and through) the PIX firewall.

- Jouni

junaid haroon · ‎05-21-2013

Hi

okay please check below acl is correct.

access-group internet_control in interface inside

access-list internet_control permit IP 192.168.0.-30 0.0.0.255

access-list internet_control permit IP 192.168.200.-254 0.0.0.255

access-list internet_control deny IP any any.

Jouni Forss · ‎05-21-2013

Hi,

You CANT use any form of address ranges either on the ACLs or the NAT configurations on your software level.

Also you CANT use willcard masks on a Cisco firewall. Those are used on Routers but not firewalls

The configuration I provided should be the configuration you can use on your PIX firewall.

You will have to take into account that you have L2L VPN connections and VPN Client configurations on the PIX too and that traffic has to be allowed too or those stop working from your LAN to the remote site. That is why I had added some ACL rules on top of the ACL

So you should be ok with

object-group network ALLOWED-INTERNET

network-object 192.168.0.0 255.255.255.224

network-object 192.168.0.200 255.255.255.248

network-object 192.168.0.208 255.255.255.248

network-object 192.168.0.216 255.255.255.248

network-object 192.168.0.224 255.255.255.224

access-list INSIDE-IN remark Allow traffic to remote sites

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.1.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.2.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.3.0 255.255.255.0

access-list INSIDE-IN permit ip 192.168.0.0 255.255.255.0 192.168.10.0 255.255.255.0

access-list INSIDE-IN remark Allow Internet for some users

access-list INSIDE-IN permit ip object-group ALLOWED-INTERNET any

access-list INSIDE-IN remark Deny all other users

access-list INSIDE-IN deny ip 192.168.0.0 255.255.255.0 any

access-group INSIDE-IN in interface inside

It first allow traffic to all the VPN networks. It then allows all traffic from the selected hosts that you mentioned in your original post. It then BLOCKS ALL OTHER traffic from the "inside"

- Jouni

junaid haroon · ‎05-21-2013

Hi,

Great thanks for Help.But jouni i am still struck in "IN" and "OUT" statements with respect to ACL.As far my understanding.

"IN" mean inbound traffic and "out" mean outbound traffic with respect to interface.

Mean when traffic going from our LAN to firewall inside interface we call it outbound traffic am i right??/

Jouni Forss · ‎05-21-2013

Hi,

Inbound and Outbound traffic can be controlled in the interface ACL by choosing the direction "in" or "out"

Inbound means traffic coming towards the interface

Outbound means traffic going out/heading out the interface

Here is a simple picture that should clarify this (click on the picture to enlarge)

So if you want to control traffic towards any remote network on the "inside" interface then you use an INBOUND ACL on the interface "inside". As you can see if your PC would be connecting to the Internet then the PIX would consider that INBOUND traffic on its "inside" interface.

Same goes for "outside". You control traffic coming from networks behind "outside" interface with an INBOUND ACL on the "outside" interface.

You very rarely need to use OUTBOUND ACL or atleast I have very rarely seem them being used.

Please, Remember to mark if you have found the replys to be correct answer to your question and/or rate answers using the starts at the bottom of the reply.

Hope this helps

- Jouni