10-11-2013 03:13 PM - edited 03-07-2019 03:59 PM
I'm having a strange problem, maybe someone can help. Here's the situation:
172.17.5.0/24 --- (Vlan2134) CAT-4948-10G (Vlan2139) ---- 172.18.0.0/16
interface Vlan2134
description TDP-TECH
ip address 172.17.5.253 255.255.255.0
interface Vlan2139
ip address 172.18.0.253 255.255.0.0
ip access-group LOCKS-IN in
ip access-group LOCKS-OUT out
I have a ping running, going from 172.17.5.162 to 172.18.0.22. Everything is fine, not sure why it's truncated, though.
$ ping 172.18.0.22
PING 172.18.0.22 (172.18.0.22) 56(84) bytes of data.
40 bytes from 172.18.0.22: icmp_req=1 ttl=63 (truncated)
40 bytes from 172.18.0.22: icmp_req=2 ttl=63 (truncated)
40 bytes from 172.18.0.22: icmp_req=3 ttl=63 (truncated)
^C
--- 172.18.0.22 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 2.055/2.106/2.149/0.053 ms
The ACLs are defined on the interface, but they haven't actually been configured. If my goal was to allow only these pings, and nothing else, wouldn't a reasonable ACL be something like this:
ip access-list extended LOCKS-IN
permit icmp 172.17.5.0 0.0.0.255 172.18.0.0 0.0.255.255 echo
ip access-list extended LOCKS-OUT
permit icmp 172.18.0.0 0.0.255.255 172.17.5.0 0.0.0.255 echo-reply
?
Because when I turn them on, I get this output on my ping:
40 bytes from 172.18.0.22: icmp_req=22 ttl=63 (truncated)
From 172.17.5.253 icmp_seq=36 Packet filtered
From 172.17.5.253 icmp_seq=38 Packet filtered
From 172.17.5.253 icmp_seq=43 Packet filtered
From 172.17.5.253 icmp_seq=48 Packet filtered
From 172.17.5.253 icmp_seq=53 Packet filtered
Does anybody know what's going on here?
This is the version:
Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500-IPBASEK9-M), Version 15.0(2)SG7, RELEASE SOFTWARE (fc2)
Thanks,
Stephan
Solved! Go to Solution.
10-11-2013 04:20 PM
Stephan,
I think you need to reverse your access lists
You have
ip access-list extended LOCKS-IN
permit icmp 172.17.5.0 0.0.0.255 172.18.0.0 0.0.255.255 echo
ip access-list extended LOCKS-OUT
permit icmp 172.18.0.0 0.0.255.255 172.17.5.0 0.0.0.255 echo-reply
+++++++++++++++++++++
Try
ip access-list extended LOCKS-IN
permit icmp 172.18.0.0 0.0.255.255 172.17.5.0 0.0.0.255 echo-reply
ip access-list extended LOCKS-OUT
permit icmp 172.17.5.0 0.0.0.255 172.18.0.0 0.0.255.255 echo
The packets coming IN to the vlan interface will be sourced from 17.18.0.0./16
Regards,
Alex.
Please rate useful posts.
10-11-2013 04:20 PM
Stephan,
I think you need to reverse your access lists
You have
ip access-list extended LOCKS-IN
permit icmp 172.17.5.0 0.0.0.255 172.18.0.0 0.0.255.255 echo
ip access-list extended LOCKS-OUT
permit icmp 172.18.0.0 0.0.255.255 172.17.5.0 0.0.0.255 echo-reply
+++++++++++++++++++++
Try
ip access-list extended LOCKS-IN
permit icmp 172.18.0.0 0.0.255.255 172.17.5.0 0.0.0.255 echo-reply
ip access-list extended LOCKS-OUT
permit icmp 172.17.5.0 0.0.0.255 172.18.0.0 0.0.255.255 echo
The packets coming IN to the vlan interface will be sourced from 17.18.0.0./16
Regards,
Alex.
Please rate useful posts.
10-11-2013 05:02 PM
Not so strange, after all! Thanks Alex!
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