02-10-2005 04:31 AM - edited 02-20-2020 11:55 PM
What is the best way and recommended way to create an ACL to deny incoming traffic from certain internet hosts? (Spammers, Malwares, etc)
Create a network-group and add their IPs to that group one at a time. Deny this group from the outside interface?
Any pointer is appreciated. By the way, how do you guys create/modify acl entries when there are entries in the acl already and you want to put the new line at the top or in the middle or something. Is using a telnet client with cut and paste functionality the only way?
Thanks, Eric
02-10-2005 04:58 AM
Eric,
I would go with Object-grouping method, on you question for ACL editing, I write my ACLs on notepad editor and then cut/paste back onto the firewall. This way any mistakes can be rectified before going live!
Hope this helps.
Jay
02-10-2005 05:31 AM
AFAIK, there isn't any direct possibility how to edit entries/lines in ACLs. There are not line numbers or something similar. So if you made a mistake you have to start it all over.
I tried to write ACL in editor(like notepad) and then passed it to firewall. I found that this is not possible(I didn't work for me; maybe I am not clever though ;o)
02-10-2005 05:48 AM
morbfrhtc
Sorry to have to correct you but you can edit ACL's in the manner that ewong0088 has specified.
ewong0088
Look at the example below which will hopefully clarify matters.
sh access-list inside_access_in
access-list inside_access_in line 1 permit tcp any host ukjpm001 eq tacacs (hitcnt=87378)
access-list inside_access_in line 2 permit udp any host ukjpm001 eq radius (hitcnt=1879)
access-list inside_access_in line 3 permit udp any host ukabc001 eq radius (hitcnt=1259)
access-list inside_access_in line 4 permit udp any host ukdef001 eq radius (hitcnt=18)
access-list inside_access_in line 5 permit udp any host ukdmz001 eq radius (hitcnt=122977)
no access-list inside_access_in line 3 permit udp any host ukabc001 eq radius (hitcnt=1259)
sh access-list inside_access_in
access-list inside_access_in line 1 permit tcp any host ukjpm001 eq tacacs (hitcnt=87378)
access-list inside_access_in line 2 permit udp any host ukjpm001 eq radius (hitcnt=1879)
access-list inside_access_in line 3 permit udp any host ukdef001 eq radius (hitcnt=18)
access-list inside_access_in line 4 permit udp any host ukdmz001 eq radius (hitcnt=122977)
Should you wish, you can also apply remarks at any point in the ACL, although I would recommend placing them at the top to clearly identify the ACL's role.
Steve.
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