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TOPIC: Issue w/ allowing ping through PIX Firewall - No NAT

Issue w/ allowing ping through PIX Firewall - No NAT 6 years 3 weeks ago #35550

  • SamDS
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I have a Cisco PIX firewall version 6.3 connected on one interface (eth1) to a linux PC ( in subnet and on the other (eth0) to a SoHo router (interface IP in network - behind the router is the network I would like to allow ping through it and I don't want to perform NAT.

So I went on and did exactly what is described here: Two interfaces without NAT... but I doesn't work.

Here is my config:

pixfirewall# sh ru
: Saved
PIX Version 6.3(5)
interface ethernet0 auto
interface ethernet1 auto
interface ethernet2 auto shutdown
interface ethernet3 auto shutdown
interface ethernet4 auto shutdown
interface ethernet5 auto shutdown
nameif ethernet0 outside security0
nameif ethernet1 inside security100
nameif ethernet2 intf2 security4
nameif ethernet3 intf3 security6
nameif ethernet4 intf4 security8
nameif ethernet5 intf5 security10
enable password 8Ry2YjIyt7RRXU24 encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
hostname pixfirewall
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
pager lines 24
logging buffered debugging
mtu outside 1500
mtu inside 1500
mtu intf2 1500
mtu intf3 1500
mtu intf4 1500
mtu intf5 1500
ip address outside
ip address inside
no ip address intf2
no ip address intf3
no ip address intf4
no ip address intf5
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 inside
no failover ip address intf2
no failover ip address intf3
no failover ip address intf4
no failover ip address intf5
pdm history enable
arp timeout 14400
nat (inside) 0 0 0
conduit permit icmp any any
route outside 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
no snmp-server location
no snmp-server contact
snmp-server community public
no snmp-server enable traps
no floodguard enable
telnet timeout 5
ssh timeout 5
console timeout 0
terminal width 80
: end

The LINK llights are ON.
The router is, I believe, properly configured.
Help please ?
The administrator has disabled public write access.

Re: Issue w/ allowing ping through PIX Firewall - No NAT 6 years 2 weeks ago #35597

  • S0lo
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Identity NAT appears to be miss-configured. Remove this command:

nat (inside) 0 0 0

And replace it with

nat (inside) 0 0 0

This should basically allow the linux PC to ping the Soho network, but NOT vise versa. If this doesn't work, try:

nat (inside) 0 0 0

If no use, give us more details including the config of the router.
Studying CCNP...

Ammar Muqaddas
Forum Moderator
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Re: Issue w/ allowing ping through PIX Firewall - No NAT 6 years 2 weeks ago #35600

  • SamDS
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Thank you for your answer, actually I figured out what the problem was.

Our firewall was a “standby” unit (back up firewall), so we had to define failover IP addresses.

failover ip address outside

failover ip address inside

After that we could ping the firewall from host and vice-versa.

Have a nice day,
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