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PIX501 - inside interface subnet change

Here is my current configuration. It seems to be working great in my test environment. I have two computers connected to this router. InsidePC connected inside (eth1) is able to access files shared on Server which is connected to the outside (eth0). All computers inside are able to ping outside. Outside should have no access/ports open to the inside.

My PC's on my real network have ip address's 172.31.1.1 - 254 /

255.255.0.0 My InsidePC's IP address needs to be 172.31.1.136 subnet 255.255.0.0 Currently in this cisco test environment I have InsidePC set to 172.31.4.136 / 255.255.255.0.

Can I change my PIX inside configuration to work with my PC address

172.31.1.136 / 255.255.0.0 ? If possible I would like the inside interface to stay at 172.31.4.10 but possibly the subnet would be 255.255.0.0.

Thanks. If that's too confusing then let me know what I need to clarify.

Building configuration... : Saved : PIX Version 6.3(5) interface ethernet0 auto interface ethernet1 100full nameif ethernet0 outside security0 nameif ethernet1 inside security100 enable password 8Ry2YjIyt7RRXU24 encrypted passwd 2KFQnbNIdI.2KYOU encrypted hostname pixfirewall domain-name ciscopix.com clock timezone CST -6 clock summer-time CDT 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 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 name 172.31.13.1 Server name 172.31.4.136 InsidePC object-group service FileShareTCP tcp port-object eq netbios-ssn port-object eq 445 object-group service FileShareUDP udp port-object eq netbios-ns port-object eq netbios-dgm port-object eq 445 access-list FileShare permit tcp host InsidePC host Server object-group FileShareTCP access-list FileShare permit udp host InsidePC host Server object-group FileShareUDP access-list FileShare permit icmp any any pager lines 24 logging on logging console alerts logging monitor alerts logging buffered informational icmp permit any outside icmp permit any inside mtu outside 1500 mtu inside 1500 ip address outside 172.31.13.2 255.255.255.0 ip address inside 172.31.4.10 255.255.255.0 ip audit info action alarm ip audit attack action alarm pdm location InsidePC 255.255.255.255 inside pdm logging informational 100 pdm history enable arp timeout 14400 global (outside) 1 interface nat (inside) 1 InsidePC 255.255.255.255 0 0 access-group FileShare in interface outside 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 172.31.4.0 255.255.255.0 inside no snmp-server location no snmp-server contact snmp-server community public no snmp-server enable traps floodguard enable telnet 172.31.4.0 255.255.255.0 inside telnet timeout 5 ssh timeout 5 console timeout 0 terminal width 80 Cryptochecksum:de64665191c7faff9ddde4375cba0cc4 : end [OK]
Reply to
Matt Scoff
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If I understand your question correctly, you would like to have inside machines (172.31.1.x) use this pix as their default gateway, but would like to avoid having to change the IP address of inside interface of the PIX (remain 172.31.4.10)

I don't know what the rest of your network looks like, but I suppose you could setup your inside interface as 172.31.4.10 with a subnet of

255.255.248.0. This would allow you to use anything between 172.31.0.0 and 172.31.7.255. You would have to change the default gateway of the PC's on the inside (guessing, as I don't know what you currently have going on).

NOT 255.255.0.0, as this will conflict with your outside interface address, and that won't work.

Matt Scoff wrote:

Reply to
Kevin Widner

Thank you. I will give that a shot. It would be nice if I did not need to change the default gateway on the PC, but i'm not sure how else I could do this.

Here's the final goal:

PC (172.31.1.136 / 255.255.0.0) | | Internal Network__________ (Watchguard Firewall port1)____Internet | | |eth1 (inside) Cisco 501 Pix |eth0 (outside) | | Server NIC1(172.31.13.1) NIC2 ______________________(Watchguard Firewall port2)___Internet

The watchguard is one appliance with two ports inside, one outside to internet. It's hard to draw here. The Server is in a sort of DMZ zone that only allows Inside PC to access it from the inside.

The problem if I change the default gatway on my Inside PC which is not the ip address of watchguard (172.31.4.2) to 172.31.4.10 then I will not be able to access the internet.

Maybe there is a better way?

Reply to
Matt Scoff

Do you have a DHCP server?

Reply to
Jonathan Roberts

No. All static IP address's on my network.

I changed the inside interface to 172.31.4.10 / 255.255.248.0

I change my PC to the desired 172.31.1.136 / 255.255.0.0

From my PC I am able to ping the inside interface (172.31.4.10) but not my server (172.31.13.1) on the outside interface. Do I need to change something else?

Reply to
Matt Scoff

I forgot the nat entry for the new ip. That helped, but it appears that I must change the PC to 172.31.1.136 /255.255.248.0 for it to work correctly. Is that true?

Reply to
Matt Scoff

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