ICMP - change DSCP drops packets

Chateau C12
RouterOS v7.1beta1
default config

I am working on QoS and marking packets. PC > router (bridge > lte1) > Internet

/ip firewall mangle add action=change-dscp chain=prerouting comment="mark ICMP packets (DSCP 46)"\
 dscp=!46 in-interface=bridge new-dscp=46 passthrough=yes protocol=icmp

Above by mangle rule changes DSCP in ICMP packet but it is lost somewhere and results in

Request timeout for icmp_seq

. I cannot find anything wrong in logs.

If I try ping directly from router it works. If I disable this rule, ping works.

I am not sure whether it is a bug or not but DSCP marked ICMP do not pass via router and back.

it looks like “change-dscp” in firewall/mangle is full of bugs not only for ICMP.

Yesterday, local DNS cache stopped to work and whole Internet connectivity was down.

I have to switch off all “dscp” mangle rules.

2020-07-25_supout.rif.zip (543 KB)