I've ran wireshark on our app server and noticed a reset packet is commonly being received when sending data to a remote telnet server when the connection has been idle for an hour or so.
I've read that our local firewall (ASA5505) may be sending this reset packet to clean up "old" connections, and that the ASA series is commonly known for this because of it's low default timeouts. Is there any way I can prove whether or not the ASA is responsible or whether the packet is coming from some other source, e.g. running a packet sniffer on the firewall to see if the packet is ever received?