This is a VERY simple setup. The ASA is running in transparent mode with an inside and outside interface. The ACLs allow ip and icmp any/any. But every couple of minutes you cannot ping through the ASA. The 1800 router goes out to a WAN.
Running continuous windows pings from the host to the RTR interface IP will hum right along and then stop for exactly 30 seconds, then resume. There are no link or spanning-tree transitions on the 3750 switch ports involved.
Any thoughts on what to look for? 30 seconds sounds way to close to spanning-tree going through listening/learning again. Also the link between the 1800 and ASA outside interface was acting unusual - leaving auto/auto speed/duplex resulted in 100/full on both ends. Forcing 100/full on both ends resulted in no link on either end which is really unusual.
Thanks in advance for any ideas.