Hello all, this is my first post here.
Currently I'm working on a project where I have a Modbus TCP\IP communication through a Cisco ISR 4321 and there is a strange behavior that I will describe.
Device "A" > IP: 10.118.67.17/29
SVI Vl220 > IP: 10.118.67.22/29
Device "B" > IP: 10.118.66.233/29
Device "C" > IP: 10.118.66.234/29
SVI Vl224 > IP: 10.118.66.238/29
Device "A" is connected to G0/2/6 (SVI Vl220), device "B" is connected to G0/1/3 (SVI Vl224). When I try to ping device B from ISR 4321, using "ping 10.118.66.233 source Vl220" it's working but reverse, "ping 10.118.67.17 source Vl224" ping fails. It happens exactly the same with device "C". I've deleted both VLANs, SVI, reset do default all three physical interfaces and configured everything back and result was the same. After this I've moved device "B" to another unused interfaces, add to a new VLAN and configured a new IP address and this time it's working fine. Then moved device "C" to different interface, in the same VLAN as "B" but when I tried to ping again with source interface, using the new IPs, same result. Looks like ping is working only in one direction. There is no ACL that could block ICMP.
Unfortunately, in this moment I don't have access to extract the running-configuration and paste is here. I tried to explain as good as I could.
I run out of ideas and I need your help, thanks.
