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Applying ACL to Outside interface

mnlatif
Level 3
Level 3

I am testing a PIX before it goes into production network. Maybe i am making a very stupid mistake but i am having troublke in applying an Access list to outside interface. Here is the partial config

+++++++++++++++++++++++++++

nameif ethernet0 outside security0

access-list 103; 2 elements

access-list 103 deny icmp any any (hitcnt=0)

access-list 103 deny ip any any (hitcnt=0)

ip address outside x.x.x.60 255.255.255.248

access-group 103 in interface outside

++++++++++++++++++++++++++++++++++++++++++++++++

But when i ping the outside interface from a client (x.x.x.57), it responds to the pings, however it should have denied based on the Access List.

Below is the capture

______________________________

11:31:09.856507 x.x.x.60 > x.x.x.57: icmp: echo reply(fragment-packet)

11:31:09.858018 X.x.x.57 > x.x.x.60: icmp: echo request(fragment-packet)

________________________________________________

6 Replies 6

rais
Level 7
Level 7

What does it mean by (fragment-packet)? Did you try sysopt security fragguard feature?

Thanks.

Still the same thing with sysopt security fragguard feature.

I think you will only be able to ping the FW's outside interface. Nothing Inside.

Rais.

Actually it is forwarding traffic for other hosts. Below 10.1.1.1 doesn't exist but the PIX ACL did allow this traffic to come inside.

12:37:14.342053 x.x.x.57 > 10.1.1.1: icmp: echo request(fragment-packet)

12:37:16.341245 x.x.x.57 > 10.1.1.1: icmp: echo request(fragment-packet)

I only see echo request in your debug output. Are you getting replies as well on the .57 machine?

Thanks.

I should have use..(config)#icmp permit|deny .... command.

It seems ICMP Packets destined towrds an interface are not controlled by ACL statements.