04-02-2004 04:49 PM - edited 02-20-2020 11:19 PM
I am trying to setup a PIX 501 firewall that sits behind a DSL modem on a home network that consists of three PC's. I have the PIX setup as a dhcp server for the inside interface. It seems to be assigning addresses ok to the PC's. I can ping an outside ip from within the PIX, but I cannot access any web pages via a browser from any of the computers on the LAN. I can see the dns info, so that looks like its ok. when I try to connect to the internet, the firewall logs the following "710005: UDP request discardedfrom10.0.1.104/137toinside:10.255.255.255/netbios-ns" and thats it.
firewall is setup as below. please help. thanks
interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password xxxxx
passwd xxxxx
hostname pixfirewall
fixup protocol ftp 21
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol http 80
fixup protocol ils 389
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
names
pager lines 24
logging on
logging buffered debugging
mtu outside 1500
mtu inside 1500
ip address outside pppoe setroute
ip address inside 10.0.1.100 255.0.0.0
ip audit info action alarm
ip audit attack action alarm
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:
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
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
telnet 10.0.0.0 255.0.0.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
vpdn group DSL request dialout pppoe
vpdn group DSL localname xxxx
vpdn group DSL ppp authentication pap
vpdn username xxxx password *********
dhcpd address 10.0.1.102-10.0.1.110 inside
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd enable inside
terminal width 80
04-03-2004 12:54 AM
can you crank up debug logging for pppoe? what outside ip can you ping? are you getting an external ip address from your isp?
04-03-2004 07:31 AM
I found that if I manually specify a set of dns servers using the "dhcpd dns" command, that I can browse the internet. still not sure why the dhcp wasn't getting this automatically. I could ping any valid outside address from the FW all along, and I could enter the ip address of a site in the browser instead of the hostname and it would work fine. would like to know why the dns wasn't getting through automatically, if anyone has any thoughts? at least it is working though. thanks
04-05-2004 03:28 PM
Please forgive this post since I am not an expert or have any expierience in the PIX 501. Three weeks ago, I purchased a PIX 501 and tried to install it with two desktop and one laptop computer to safely share the Internet. Thru much help with the ARS networking board and this particular forum, everything works super. The pix shares 3 computers and also one access point for wireless laptop. The only differences between yours and my config are listed below. If you have already found the answer, that's great. I am only saying below works for me. Good Luck, it was very stressful until the final instruction made it work.
hostname pixfirewall
--------------> domain-name ciscopix.com
fixup protocol ftp 21
pager lines 24
--------------> icmp permit any unreachable outside
logging on
aaa-server LOCAL protocol local
--------------> http server enable
--------------> http 192.168.1.0 255.255.255.0 inside
no snmp-server location
dhcpd ping_timeout 750
--------------> dhcpd auto_config outside
dhcpd enable inside
04-05-2004 04:20 PM
In this case, the PIX is both a DHCP client and a DHCP server. As a DHCP client, it was recieving DNS info from your ISP and could probably resolve things just fine. Your inside computers, however, are relying on THEIR DHCP server (in this case, the PIX) to provide them with all the info they need. So yes, "dhcpd dns" must be set in order for your client computers to get all of their info.
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