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Pix Firewall 506, blocking ip addresses

chris_nt
chris_nt asked
on
Medium Priority
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Last Modified: 2013-11-16
Hello, I need to know how to block a list of public ip addresses in the pix, I have searched and found references to blocking ranges of ip address, but had no luck on just one, or in my case about 10 outside addresses.

Basically, we are trying to block access to some sites like myspace and stuff until we can get an ISA server up and going.

I know this is pretty simple,  but I need an answer quick so I am offering lots of points.
I am looking for the CLI commands.

Thanks in advance

Chris.
Comment
Watch Question

Have you tried just using regular ACL's on the outside interface?

deny ip host x.x.x.x any ?

or

deny ip host x.x.x.x any eq 80?

Author

Commented:
seems I need a little more input, here is what I did

access-list inside_out deny ip host 216.109.126.22 any
access-group inside_out in interface inside

but when I did it shut down all of the internet

you need an implicit permit ip any any.... does that help at all?

Commented:
you have the right idea but doing it the other way around... You wan to block traffic originating from the inside going to outside. try this...

        access-list inside_out_blocked deny ip any host 216.109.126.22
        access-list inside_out_blocked permit ip any any

        access-group inside_out_blocked in interface inside

be sure to remove the old access-list
Saif

Author

Commented:
Thanks I think that is what I need, I will see if it will work this afternoon.

Author

Commented:
Well that is getting close, that works for one ip address, do I need to make a new access list for every ip? ie inside_out_blocked1, inside_out_blocked2.... and so on for each IP address? or is there a way to have a list for one access list.  I need to block about 20 ip addresses

Thanks.
Commented:
for multiple ip you could just to the same access-list like so...

first do this... you need to remove this line from the access list because ordering is important in access lists and this permits access to all sites.

        no access-list inside_out_blocked permit ip any any

then you build your access-list with all the IPs you want to block.

        access-list inside_out_blocked deny ip any host 1.1.1.1
        access-list inside_out_blocked deny ip any host 2.2.2.2
        access-list inside_out_blocked deny ip any host 3.3.3.3
        access-list inside_out_blocked deny ip any host 4.4.4.4
        access-list inside_out_blocked permit ip any any

Then you apply the access-list to your interface, but you have already done that so you can skip this step.

        access-group inside_out_blocked in interface inside

Saif

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Author

Commented:
that's what I pretty much figured out, but you are the man, for some resone my last post did not show up. one last question though.  do i need to undo (no) the

     access-list inside_out_blocked permit ip any any
     access-group inside_out_blocked in interface inside

then add new ip's then and redo? or should i just need to add the

     access-list inside_out_blocked deny ip any host ?.?.?.?

when i need to add a new ip.

thanks

Commented:
you'll just need to remove (no) the following line...
     
        access-list inside_out_blocked permit ip any any

then add what ever IPs you want to add to the access-list

        access-list inside_out_blocked deny ip any host x.x.x.x

then just allow everything again...

        access-list inside_out_blocked permit ip any any

on the PIX everything happens in real time... so when you remove the 'permit ip any any' line from the access-list all out going access will be stopped until you put it back in... so keep that in mind. Thanks for the points... :)

Saif

Author

Commented:
That's exactly what I needed to know, thanks.  I hope this thread will be of help to other people.
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