I think it was ASA 8.3 that began to provide an option to NOT cease functionality when tcp syslog server was unreachable. In ASDM, it is a checkbox at the bottom of the logging servers config section. Sent from my iPhone On Nov 20, 2011, at 7:43, Joe Happe <Joe.Happe@archlearning.com> wrote:
Completely agree with splunk for log searching / analysis, even has some ASA/PIX modules. Please note, unless something has changed that I completely missed, an ASA/PIX will stop forwarding user traffic if it is configured for tcp syslogs and the connection breaks. (no more disk, network issue, etc) This is based on the premise that a system cannot be considered secure if the audit trail is unavailable, and tcp syslogging(vs udp) is usually used to make sure you don't miss an entry due to a dropped packet. Something that dates back to the old C2 security standard??(not sure of the current version). Typically this requires admin intervention (by design) to clear the condition. If you use udp for syslog the ASA won't be in this mode, and you won't block traffic if syslog fails. With that said, there may be a command I'm unaware of that allows a tcp syslog to fail and not block traffic.
~jdh