02-27-2003 05:33 PM - edited 02-20-2020 09:20 PM
Hey all, please forgive my ignorance on the pix os and acls, but I am missing something.
I start with a pix out of the box. I can set it up with no acl's and can browse the net, dowload kazaa, etc., just like I thought. I apply 3 acl's and I can not do a thing. below is the before config file, the commands i issued, and the after config file. A little background, pix connected to cable modem with dynamic ip address. What am I missing?
Thanks in advance
XXXXXXXXXXX(config)# sh run
: Saved
:
PIX Version 6.2(2)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password XXXXXXXXXXXXXXX encrypted
passwd XXXXXXXXXXXXXXX encrypted
hostname XXXXXXXXXXXX
domain-name XXXXXXXXXXXX
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol ils 389
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 10baset
interface ethernet1 10full
mtu outside 1500
mtu inside 1500
ip address outside dhcp setroute
ip address inside 192.168.100.2 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
pdm logging informational 100
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 0:05:00
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
aaa-server LOCAL protocol local
http server enable
http 192.168.100.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
no sysopt route dnat
telnet 192.168.100.0 255.255.255.0 inside
telnet timeout 5
ssh timeout 5
dhcpd address 192.168.100.10-192.168.100.99 inside
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd auto_config outside
dhcpd enable inside
terminal width 80
Cryptochecksum:7b4ee383b106a8b8c60d546296d022df
: end
The commands
XXXXXXXXXXX(config)# access-l 100 permit tcp any any eq 80
XXXXXXXXXXX(config)# access-l 100 permit tcp any any eq 53
XXXXXXXXXXX(config)# access-l 100 permit tcp any any eq 110
XXXXXXXXXXX(config)# access-g 100 in interface inside
The after
XXXXXXXXXXXX(config)# sh run
: Saved
:
PIX Version 6.2(2)
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password XXXXXXXXXXXXXXXXX encrypted
passwd XXXXXXXXXXXXXXXX encrypted
hostname XXXXXXXXXXXXXX
domain-name XXXXXXXXXXXXXXX
fixup protocol ftp 21
fixup protocol http 80
fixup protocol h323 h225 1720
fixup protocol h323 ras 1718-1719
fixup protocol ils 389
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
access-list 100 permit tcp any any eq www
access-list 100 permit tcp any any eq domain
access-list 100 permit tcp any any eq pop3
pager lines 24
interface ethernet0 10baset
interface ethernet1 10full
mtu outside 1500
mtu inside 1500
ip address outside dhcp setroute
ip address inside 192.168.100.2 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
access-group 100 in interface inside
timeout xlate 0:05:00
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
aaa-server LOCAL protocol local
http server enable
http 192.168.100.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
no sysopt route dnat
telnet 192.168.100.0 255.255.255.0 inside
telnet timeout 5
ssh timeout 5
dhcpd address 192.168.100.10-192.168.100.99 inside
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd auto_config outside
dhcpd enable inside
terminal width 80
Cryptochecksum:7b4ee383b106a8b8c60d546296d022df
: end
02-27-2003 10:02 PM
With that ACl applied to the inside interface the PIX is dropping all the traffic, you should not apply that at all ,if you need to really control it, the ACL should like
access-list 100 deny ip any any
access-list 100 permit tcp any eq www any
access-list 100 permit tcp any any eq domain
access-list 100 permit tcp any any eq pop3
04-28-2003 12:21 AM
I have little confusion, if we deny ip packets ,how it will work at layer 4.
I mean wud'nt it be an implicit deny. sud we to add
permit ip any any at the end ??
02-28-2003 06:26 AM
by default, pixen allow all outbound traffic out, and nothing in (unless it is a stateful response to an outbound request). By applying an acl to the inside int, you restrict outbound traffic to only that which you explicitly permit in the ACL
03-27-2003 01:11 AM
Your web traffic is allowed. However, your DNS is not. Instead of opening up UDP/53, you opened TCP/53. You need to open up UDP/53 for the name ressolution, and if you have authoritative DNS server in your network, then tcp/53 is required to be opened for the zone transfer. So, just add the following line on your existing config and then you should be able to start browsing.
access-l 100 permit udp any any eq 53
After entering the above line, please execute "clear xlate" and "clear arp" if you still have any issues.
03-27-2003 01:13 AM
Also, please note that you are opening POP3. If you are using SMTP for your e-mail client then you will run into problem. Just a FYI.
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