How to allow all outgoing traffic and block all incoming traffic with access list?

HardTrickySecurity · Aug 30, 2015

Using Cisco PIX 515E firewall
Version 7.2(4)25
Unrestricted (UR) license

This is my current configuration:

config t
int e0
ip address dhcp setroute
nameif outside
no shut

int e1
ip address 10.1.1.1 255.0.0.0
nameif inside
no shut
exit

global (outside) 1 inter
nat (inside) 1 10.0.0.0 255.0.0.0

icmp deny any outside

iggsterman · Aug 30, 2015

By default (providing the required translations are configured between the interfaces) the traffic from interfaces with higher security levels to those with lower security is allowed and it is is blocked in the opposite direction. PIX will assume security level 0 for the nameif "outside" and 100 for "inside". So you should be all set. Still for clarity I would add under int e0:
[pre]security-level 0[/pre]
and under e1:
[pre]security-level 100[/pre]

You may also find this Link useful.

navypop42 · Sep 1, 2015

I would suggest the following:

access-list acl_out extended deny ip any any

access-group acl_out in interface outside

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How to allow all outgoing traffic and block all incoming traffic with access list?

HardTrickySecurity

Technical User

iggsterman

Technical User

navypop42

Technical User

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