Ubuntu 18.04 squid wccp issue

Hi all,

We have squid proxy server on Ubuntu 16.04 in our company and use Cisco ASA redirects the Internet traffic through wccp tunnel. We planed to upgrade the Ubuntu to 18.04 recently.

I setup the new proxy server on Ubuntu 18.04 in a test environment, but the wccp didn't work.

Here are the configurations and some troubleshooting steps I have taken:

### Squid config
---
acl localnet src 0.0.0.1-0.255.255.255  # RFC 1122 "this" network (LAN)
acl localnet src 10.0.0.0/8             # RFC 1918 local private network (LAN)
acl localnet src 100.64.0.0/10          # RFC 6598 shared address space (CGN)
acl localnet src 169.254.0.0/16         # RFC 3927 link-local (directly plugged) machines
acl localnet src 172.16.0.0/12          # RFC 1918 local private network (LAN)
acl localnet src 192.168.0.0/16         # RFC 1918 local private network (LAN)
acl localnet src fc00::/7               # RFC 4193 local private network range
acl localnet src fe80::/10              # RFC 4291 link-local (directly plugged) machines

acl SSL_ports port 443
acl Safe_ports port 80          # http
acl Safe_ports port 21          # ftp
acl Safe_ports port 443         # https
acl Safe_ports port 70          # gopher
acl Safe_ports port 210         # wais
acl Safe_ports port 1025-65535  # unregistered ports
acl Safe_ports port 280         # http-mgmt
acl Safe_ports port 488         # gss-http
acl Safe_ports port 591         # filemaker
acl Safe_ports port 777         # multiling http
acl CONNECT method CONNECT

#http_access deny !Safe_ports
#http_access deny CONNECT !SSL_ports
http_access allow localhost manager
http_access deny manager
http_access allow localnet
http_access allow localhost

http_access allow all    # allow all for test

http_port 3128 intercept
http_port 3127

cache_store_log daemon:/var/log/squid/store.log

coredump_dir /var/spool/squid

#url_rewrite_program /usr/sbin/ufdbgclient -m 4 -l /var/log/squid
#url_rewrite_children 16 startup=8 idle=2 concurrency=4 queue-size=64

refresh_pattern ^ftp:           1440    20%     10080
refresh_pattern ^gopher:        1440    0%      1440
refresh_pattern -i (/cgi-bin/|\?) 0     0%      0
refresh_pattern .               0       20%     4320

wccp2_router x.x.x.x
wccp2_forwarding_method gre
wccp2_return_method gre
wccp2_assignment_method hash
wccp2_service standard 0 password=test123    #set password on firewall to make sure only this proxy is usable
---

- I have checked the route and firewall ACL, the network part is ok.
- Specify the proxy and port in the browser's setting, the traffic can be proxied.
- Tcpdump the wccp gre tunnel, I can see the http request was redirected to the proxy server.
- No access log for the redirected traffic.
- I tried both the squid from the official repository and build script, neither worked.
- I tried replacing the ubuntu default network manager netplan with the old ifup/ifdown, not work.
- I setup the proxy on debian 10 with the exact same configuration, everything works fine.

Based on the above information, I want to know did I misconfigured something on Ubuntu1804? or it's a bug?