Symptom
Log messages showing up
Nov 17 03:00:33.985: IOSXE-INJECT: check failed, pak inject type L3 IP, ipv4 pak unknown adj case, intf Gi0/0/0
*Nov 17 03:00:33.985: IOSXE-INJECT: check type failed, fail count 1622, seqnum 63726945
*Nov 17 03:00:33.985: %LSMPI-4-INJECT_FEATURE_ESCAPE: Egress IP packet delivered via legacy inject path
Conditions
When ISR router is configured as DNS server, in some corner cases such as receiving abnormal DNS query pkts during a DNS attack, the tracebacks could be seen when UDP response pkts are fragmented in IOS.
Workaround
When DNS server is configured on ISR routers, some firewall features such as ZBF with self zone protection could prevent routers from receiving abnormal packets.
Further Problem Description
The logs are not causing any issue on customers network it seems to be an informational log or a cosmetic issue. Will see the hints when l2 inject is used as a last resort injection way.
