ACLs on router on stick. Pings not working

christoffer92 — Sat, 10 Dec 2022 09:59:28 GMT

Hello! I have run into a problem with pings. I have 3 networks on 3 vlans: students, servers and admin.

Students network is 192.168.1.0, servers network is 192.168.2.0 and admin network is 192.168.3.0.

The following config is working as intended except when I try to ping the student network from any of the other networks which blocks the icmp reply unless I add

permit icmp 192.168.1.0 0.0.0.255 192.168.3.0 0.0.0.255

permit icmp host 192.168.1.10 any

witch defeats the purpose of denying pings from the student network

Extended IP access list servers

10 permit tcp 192.168.1.0 0.0.0.255 host 192.168.2.12 eq smtp

20 permit tcp 192.168.1.0 0.0.0.255 host 192.168.2.12 eq pop3

30 permit tcp 192.168.1.0 0.0.0.255 host 192.168.2.10 eq www

40 permit tcp 192.168.3.0 0.0.0.255 host 192.168.2.10 eq www

50 permit tcp 192.168.3.0 0.0.0.255 host 192.168.2.12 eq pop3

60 permit tcp 192.168.3.0 0.0.0.255 host 192.168.2.12 eq smtp

70 permit icmp 192.168.3.0 0.0.0.255 192.168.2.0 0.0.0.255

80 permit tcp host 192.168.3.11 eq www any

90 deny ip any any

100 deny tcp any any

Extended IP access list admin

10 permit tcp 192.168.2.0 0.0.0.255 host 192.168.3.11 eq www

20 permit tcp host 192.168.2.10 eq www any

30 permit tcp host 192.168.2.12 eq smtp any

40 permit tcp host 192.168.2.12 eq pop3 any

50 permit icmp 192.168.2.0 0.0.0.255 192.168.3.0 0.0.0.255

60 deny ip any any

70 deny tcp any any

Thanks!

Re: ACLs on router on stick. Pings not working

MHM Cisco World — Sat, 10 Dec 2022 10:04:42 GMT

permit icmp 192.168.1.0 0.0.0.255 192.168.3.0 0.0.0.255 echo-reply <<- this only you need to end of your permit ACL line

Re: ACLs on router on stick. Pings not working

Rob Ingram — Sat, 10 Dec 2022 10:06:55 GMT

@christoffer92 What interface(s) have you applied the ACL and in which direction? Provide the configuration.

You could just permit echo-reply instead of icmp.

Re: ACLs on router on stick. Pings not working

christoffer92 — Sat, 10 Dec 2022 10:13:29 GMT

Wow thanks, now i feel pretty stupid!

topic Re: ACLs on router on stick. Pings not working in Network Security

ACLs on router on stick. Pings not working

Re: ACLs on router on stick. Pings not working

Re: ACLs on router on stick. Pings not working

Re: ACLs on router on stick. Pings not working