PIX 501 with multiple public IP addresses

Answered Question
Sep 3rd, 2010
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Hello all,


I have the following configuration:


6 public IP addresses, eg: 123.123.123.1 - 6 255.255.255.248

From my Provider I have a Zyxel modem which has the IP 123.123.123.1 which is also the default gateway for my PIX.

The PIX is connected to the Zyxel modem.

The outside interface of the PIX has 123.123.123.2 and the inside interface has 192.168.1.1 255.255.255.0


On my inside network I have several client computers and 3 servers.

The client computers should be able to connect to the internet.

Server A should have the public IP 123.123.123.3 and inside 192.168.52.3

Server B should have the public IP 123.123.123.4 and inside 192.168.52.4

Server C should have the public IP 123.123.123.5 and inside 192.168.52.5


The 3 server are webservers and should be accessible from the outside on port 80 and 443.


My current configuration is:


pixfirewall(config)# show run
: Saved
:
PIX Version 6.3(5)
interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password  encrypted
passwd  encrypted
hostname pixfirewall
domain-name ciscopix.com
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
fixup protocol smtp 25
fixup protocol sqlnet 1521
fixup protocol tftp 69
names
object-group service web tcp
  port-object eq www
  port-object eq https
access-list OUTSIDE permit ip any host 123.123.123.3
pager lines 24
mtu outside 1500
mtu inside 1500
ip address outside 123.123.123.2 255.255.255.248
ip address inside 192.168.1.1 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
pdm location 192.168.1.0 255.255.255.0 inside
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1 192.168.1.0 255.255.255.0 0 0
static (inside,outside) tcp 123.123.123.3 www 192.168.1.3 www netmask 255.255.255.255 0 0
access-group OUTSIDE in interface outside
route outside 0.0.0.0 0.0.0.0 123.123.123.1 1
timeout xlate 0:05:00
timeout conn 1:00:00 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 sip-disconnect 0:02:00 sip-invite 0:03:00
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
http server enable
http 192.168.1.0 255.255.255.0 inside
http 192.168.2.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
telnet 192.168.1.0 255.255.255.0 inside
telnet 192.168.2.0 255.255.255.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
terminal width 80
: end
pixfirewall(config)#



This configuration acutally only allows connections from inside to outside but no connection from the outside to Server A.


I am sure I am missing something stupid, maybe someone could give me a hint?


Mike

Correct Answer by Jennifer Halim about 6 years 10 months ago

Configuration looks absolutely correct, assuming that you are only testing connectivity to server A (123.123.123.3) as it is the only one configured.


I would suggest that you perform "clear xlate" and "clear arp", and test again. I would double check to see if your modem has the ARP entry for 123.123.123.3 and it should be pointing towards the PIX ethernet0 MAC address.

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Correct Answer
Jennifer Halim Fri, 09/03/2010 - 04:42
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  • Cisco Employee,

Configuration looks absolutely correct, assuming that you are only testing connectivity to server A (123.123.123.3) as it is the only one configured.


I would suggest that you perform "clear xlate" and "clear arp", and test again. I would double check to see if your modem has the ARP entry for 123.123.123.3 and it should be pointing towards the PIX ethernet0 MAC address.

mikepkp17 Fri, 09/03/2010 - 07:35
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Hi halijenn,


you almost saved my day. Thank you very much for the pointer to the arp entry of the modem. actually I needed to clear the arp cache of the modem, now it is working...


Maybe you can help me with another issue:


I now can access my servers from the outside but not from inside.

If I try to connect from my inside network with http://somedomain.domain.com (which resolves to 123.123.123.3) this is not working.

Is there a way to solve this problem with the PIX?


Mike

Jennifer Halim Fri, 09/03/2010 - 17:17
User Badges:
  • Cisco Employee,

Unfortunately not with the version of code you are running.

My suggestion would be to create an internal DNS entry that resolves the URL its private ip address instead of public ip address, OR/ alternatively just use the internal ip address when users are inside the network.

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