Why do many resources not work with Per Connection Classifier?

Question

Mikrotik

The problem has been around for a very long time. I remember the times when users were first transferred to PCC both addresses and ports a few years ago - as expected, a lot of problems arose, both addresses - there are noticeably fewer problems, but still enough to refuse and switch back to src-address, which in fact is not PCC, but only automates the process of distributing users across fixed channels. A month ago, the experiment with both address was repeated - the result pleased, but still, about 20% of users had to be returned back to src-address, due to complaints about the incorrect operation of some resources. The problem is generally understandable - resources that open several connections within one session want to see all connections from one source, and if the source IP address changes, they react very painfully,
Serious resources in recent years have made an obvious breakthrough in this direction, which is good, but there are also those who seem to be from another planet. In particular, Gosuslugi, Sberbank-online and others that still do not work correctly with PCC.
Wondering if anyone has experience with this problem?

Answer 1

I am currently dealing with this problem myself.
It consists in the fact that packets come through 1 provider, and leave through another.
In my case, it only breaks the VPN.
The rest of the services are working fine.