More basic questions... 2

[burtsbees]

Okay---I can't ping the outside interface from a host on the inside interface...
Cisco2620XM---PIX520---Catalyst2924
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host printer

Here's the config

PIX# sh run
: Saved
:
PIX Version 6.3(5)
interface ethernet0 auto
interface ethernet1 auto
interface ethernet2 auto shutdown
interface ethernet3 auto
nameif ethernet0 outside security0
nameif ethernet1 inside1 security95
nameif ethernet2 intf2 security4
nameif ethernet3 inside security100
enable password uxWwEdchZpppPhh9 encrypted
passwd TdMf.2OhaPbPeCCM encrypted
hostname PIX
domain-name sms.stlouis
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
pager lines 24
mtu outside 1500
mtu inside1 1500
mtu intf2 1500
mtu inside 1500
ip address outside 10.68.68.2 255.255.255.0
ip address inside1 192.168.1.69 255.255.255.0
no ip address intf2
ip address inside 10.69.69.1 255.255.255.0
ip audit info action alarm
ip audit attack action alarm
no failover
failover timeout 0:00:00
failover poll 15
no failover ip address outside
no failover ip address inside1
no failover ip address intf2
no failover ip address inside
pdm history enable
arp timeout 14400
global (outside) 1 10.68.68.128-10.68.68.254 netmask 255.255.255.0
nat (inside) 0 0.0.0.0 0.0.0.0 0 0
conduit permit icmp any any
route outside 0.0.0.0 0.0.0.0 10.68.68.1 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 rpc 0:10:00 h225 1:00:00
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 10.69.69.2 255.255.255.255 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
telnet timeout 5
ssh 192.168.69.0 255.255.255.0 outside
ssh timeout 5
console timeout 0
terminal width 80
Cryptochecksum:409c2cc31555041f7b4a17a75a1354b6
: end
Here's sh int

PIX# sh int
interface ethernet0 "outside" is up, line protocol is down
Hardware is i82558 ethernet, address is 00e0.b602.0557
IP address 10.68.68.2, subnet mask 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit half duplex
8 packets input, 564 bytes, 0 no buffer
Received 2 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
37 packets output, 2416 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collisions, 0 deferred
7 lost carrier, 0 no carrier
input queue (curr/max blocks): hardware (128/128) software (0/1)
output queue (curr/max blocks): hardware (0/1) software (0/1)
interface ethernet1 "inside1" is up, line protocol is down
Hardware is i82558 ethernet, address is 00e0.b602.0556
IP address 192.168.1.69, subnet mask 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit half duplex
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
7 packets output, 420 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collisions, 0 deferred
7 lost carrier, 0 no carrier
input queue (curr/max blocks): hardware (128/128) software (0/0)
output queue (curr/max blocks): hardware (0/1) software (0/1)
interface ethernet2 "intf2" is administratively down, line protocol is down
Hardware is i82558 ethernet, address is 00e0.b602.0555
MTU 1500 bytes, BW 10000 Kbit half duplex
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collisions, 0 deferred
0 lost carrier, 0 no carrier
input queue (curr/max blocks): hardware (128/128) software (0/0)
output queue (curr/max blocks): hardware (0/0) software (0/0)
interface ethernet3 "inside" is up, line protocol is down
Hardware is i82558 ethernet, address is 00e0.b602.0554
IP address 10.69.69.1, subnet mask 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit half duplex
73 packets input, 6505 bytes, 0 no buffer
Received 37 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
28 packets output, 2016 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collisions, 0 deferred
0 lost carrier, 0 no carrier
input queue (curr/max blocks): hardware (128/128) software (0/2)
output queue (curr/max blocks): hardware (0/1) software (0/1)

Router is doing the NAT, but I added NAT statements in the PIX anyway, since I had the same result before I added them. The router is 10.68.68.2, and my host is 10.69.69.2. The router is attached via crossover cable to the outside interface (ethernet0), and the switch is connected via straight-through cable to the inside (ethernet3). The host is connected to the switch (unlike the diagram...I am a poor editor!) Inside1 (ethernet1) is not being used right now.
What can you guys see that I am not? If the router NATs, do I still have to have NAT statements in the PIX? Like I said, I cannot ping 10.68.68.2 from the host at 10.69.69.2, and actually I cannot ping the host from the PIX (10.69.69.1 to 10.69.69.2), but I can ping the PIX (10.69.69.1) from the host (10.69.69.2), and I can ping the router from the PIX, including the router's outgoing interface. Please help---the books are unclear, and as far as I know, I have done all the basic commands for basic operation (but they never show a router on the outside NATting...).

Burt

 

[kwing112000]

I am no cisco expert but i had a PIX at home for a while and it would not even pass ping thru to the internet. I think you need to add something to allow it thru. i thought on mine there was a fix-up that i had to remove as well.

Kevin Wing
ACA- Implement IP Office
Carousel Industries

 

[burtsbees]

That's what it's looking like...after I wiped the config and kept it as basic as I could, all the fixup stuff for the PIX to inspect is there by default. I read somewhere that
nat (inside) 0 0.0.0.0 0.0.0.0
has to at least be there...but what about my router doing the NAT? Should I just let the PIX handle the NAT, and remove NAT from the router? How would the PIX know about the public address on the other side of the router?

Maybe I'll try that..

Thanks for the reply...if you remember more details, please let me know.

Burt

 

[bobbyforhire]

Looking at my pix501 in witch i'm sure you could just do the same thing.

Here is my config...hope it helps. I have some cleaning to do!!!

Result of firewall command: "sh run"


PIX Version 6.3(5)
interface ethernet0 auto
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
enable password O5QM8ExiigSz3nmh encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname CC
domain-name CompuCents.com
clock timezone EST -5
clock summer-time EDT 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 10.2.1.0 OUTSIDE_VPN
name 10.1.1.0 INSIDE
access-list outside_access_in permit icmp any any
access-list outside_access_in permit tcp any interface outside eq 6112
access-list outside_access_ing remark WEB SERVER
access-list outside_access_ing permit tcp any interface outside eq www
access-list outside_access_ing remark RSS
access-list outside_access_ing permit tcp any interface outside eq 5901
access-list outside_access_ing remark RSS
access-list outside_access_ing permit tcp any interface outside eq 5500
access-list outside_access_ing permit icmp any any
access-list outside_access_ing remark Warcraft 3 to pc QUAD
access-list outside_access_ing permit tcp any interface outside eq 6112
access-list inside_accessing_out permit icmp any any
access-list VPN_NONAT permit ip any any
access-list inside_outbound_nat0_acl permit ip any 10.2.0.0 255.255.255.224
access-list outside_cryptomap_dyn_20 permit ip any 10.2.0.0 255.255.255.224
access-list no_NAT permit ip INSIDE 255.255.255.0 10.2.0.0 255.255.255.0
access-list CCVPN_splitTunnelAcl permit ip INSIDE 255.255.255.0 any
pager lines 24
logging on
logging timestamp
logging trap notifications
logging host inside 10.1.1.20
mtu outside 1500
mtu inside 1500
ip address outside dhcp setroute
ip address inside 10.1.1.200 255.0.0.0
ip verify reverse-path interface outside
ip audit name TEST attack action alarm drop reset
ip audit name TEST1 info action alarm reset
ip audit info action alarm
ip audit attack action alarm
ip local pool VPNIP 10.2.0.1-10.2.0.30
pdm location 10.1.1.20 255.255.255.255 inside
pdm location 10.1.1.105 255.255.255.255 inside
pdm location OUTSIDE_VPN 255.255.255.224 outside
pdm location INSIDE 255.255.255.0 inside
pdm location 10.2.0.0 255.255.255.0 outside
pdm location 10.2.0.0 255.255.255.255 outside
pdm location 10.2.0.0 255.255.255.255 inside
pdm location INSIDE 255.255.255.255 inside
pdm logging informational 100
pdm history enable
arp timeout 14400
global (outside) 1 interface
nat (inside) 0 access-list no_NAT
nat (inside) 1 0.0.0.0 0.0.0.0 0 0
static (inside,outside) tcp interface

http://www 10.1.1.20

http://www netmask

255.255.255.255 0 0
static (inside,outside) tcp interface 5901 10.1.1.20 5901 netmask 255.255.255.255 0 0
static (inside,outside) tcp interface 5500 10.1.1.20 5500 netmask 255.255.255.255 0 0
static (inside,outside) tcp interface 6112 10.1.1.105 6112 netmask 255.255.255.255 0 0
static (inside,outside) tcp interface 6129 10.1.1.20 6129 netmask 255.255.255.255 0 0
access-group outside_access_ing 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 10.2.0.0 255.255.255.255 outside
http 10.0.0.0 255.0.0.0 inside
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
floodguard enable
sysopt connection permit-ipsec
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac
crypto dynamic-map outside_dyn_map 20 match address outside_cryptomap_dyn_20
crypto dynamic-map outside_dyn_map 20 set transform-set ESP-3DES-MD5
crypto map outside_map 65535 ipsec-isakmp dynamic outside_dyn_map
crypto map outside_map interface outside
isakmp enable outside
isakmp nat-traversal 20
isakmp policy 20 authentication pre-share
isakmp policy 20 encryption 3des
isakmp policy 20 hash md5
isakmp policy 20 group 2
isakmp policy 20 lifetime 86400
vpngroup CCVPN address-pool VPNIP
vpngroup CCVPN dns-server 4.2.2.2
vpngroup CCVPN split-tunnel CCVPN_splitTunnelAcl
vpngroup CCVPN idle-time 1800
vpngroup CCVPN password ********
telnet timeout 5
ssh timeout 5
management-access inside
console timeout 0
dhcpd address 10.1.1.201-10.1.1.232 inside
dhcpd dns 10.1.1.20 4.2.2.2
dhcpd lease 3600
dhcpd ping_timeout 750
dhcpd auto_config outside
dhcpd enable inside
terminal width 80
banner exec Welcome to the CC PIX 501!
banner login $(hostname)
banner motd Have a nice day!
Cryptochecksum:b94cc39490e1371e2b774737145897d9
: end

 

[FORTOREIBAS]

To ping and/or trace through a PIX, you have to allow outbound ICMP messages (inside=>outside), and you have to allow inbound ICMP replies (outside=>inside) of at least these four types: echo-reply, source-quench, time-exceeded, and unreachable.

 

[FORTOREIBAS]

Here is a snippet of how you could do it:
access-list outside_access_in permit icmp any any time-exceeded
access-list outside_access_in permit icmp any any source-quench
access-list outside_access_in permit icmp any any unreachable
access-list outside_access_in permit icmp any any echo-reply

If you have an explicit deny on inside=>outside, then add the below line
access-list inside_access_in permit icmp any any

Or, you could create an object group like this:
object-group icmp-type icmp-outside-in
icmp-object echo-reply
icmp-object time-exceeded
icmp-object unreachable
icmp-object source-quench

and use only one line of config for the outside=>inside rule, but PDM won't understand it.

 

[burtsbees]

Ah...so this is to trace and/or ping THROUGH a PIX? I know about the outside security 0 interface, but I was under the impression that it was stopping pings TO it, and not through. What about all the other regular traffic? Thanks guys---I give stars pretty freely around here...

Burt

 

[Supergrrover]

As far as I know you cannot ping the external interface from an internal source. I have tried a few combinations to test and I can't get it to respond.

Also for a trace through the pix, you will need

fixup prot icmp error

The Tracert uses a timeout to find the next hop. That hop sends a newly crafted packet and the pix doesn't know who to forward it to unless you include the error in the fixup.

Without an ACL applied to the inside interface, everything is allowed out by default. I'm a big fan of filtering traffic in all directions but I'm a little bit of a control freak. On the bright side, I run into very few problems because of it.



Brent
Systems Engineer / Consultant
CCNP, CCSP