If you have a router that traffic passes through, and you want to classify different types of traffic using DSCP values, do you need to take special care to avoid setting DSCP values on certain types of traffic?
My worry is that certain protocols that offer data integrity, like SSH or VPNs, would take a hash of the IP header, including the DSCP value, and if the DSCP value changes, the client would reject the packet.
It appears that ESP and AH, as described here take care to avoid hashing the DSCP field. Are there other protocols that aren't as careful, that might break if you change the DSCP values on their packets? Or is changing DSCP willy-nilly generally considered safe?