OS X Server System degredation

I have been observing a slow but gradual decline in system response on an OS X server over the last 2 weeks. This is a single purpose application server for Backups on the LAN (all wired) and all ssh invoked scripts via an 'rsync pull'. All that is working fine. There have been no changes to the base config, no additional users and all recent patches successfully installed. I have been manually rotating the logs in/var/log and tailing system.log to try and catch what might be happening but the ply thing that jumps out of that page is this:

Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.171.4.36!
Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.151.16.38!
Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.171.4.14!
Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.151.16.14!
Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.171.4.15!
Sep 21 11:29:52 Almighty.local _networkd[385]: on_wire failed for server 17.171.4.13!
Sep 21 11:29:52 Almighty.local ntpd[59]: proto: precision = 1.000 usec
Sep 21 11:29:59 Almighty.local ntpd[59]: ntpd: time set +0.802525 s
Sep 21 11:29:59 Almighty.local com.apple.time[207]: Interval maximum value is 946100000 seconds (specified value: 9223372036854775807).
Sep 21 11:30:10 Almighty.local ntpd[59]: FREQ state ignoring -0.000025 s

NB: We rae not on a 17.x network - could this be what is dragging the server down and if so, any ideas where the connect call might have come from?
Thank you in advance.

---------- Post updated at 11:59 AM ---------- Previous update was at 11:58 AM ----------

typo: the only thing that jumps out... (sorry)

---------- Post updated at 12:07 PM ---------- Previous update was at 11:59 AM ----------

I think the item above relates to ipV6, which on the server is configured for automatic. If that is the case, then do I need ipV6 anabled. (apologies for typo's above).

I don't think there is a straight forward (nor advisable) method to disable IPV6, but you can set it to "Link-local only", which effectively removes the overhead for actual network related tasks.

Also, it's usually helpful to mention the OS version when posting a question, as it saves back and forth communications when version specific troubleshooting could have otherwise been avoided.

Thank you for your response. Your comment on ipV6 with switch to link-local only will help. I suspect there are other issues related to hardware that need further investigation. Many thanks.