-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp -i lo -j ACCEPT
-A ISTIO_PRERT -p tcp -m tcp --dport 15008 -m mark ! --mark 0x539/0xfff -j TPROXY --on-port 15008 --tproxy-mark 0x111/0xfff
-A ISTIO_PRERT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp -m mark ! --mark 0x539/0xfff -j TPROXY --on-port 15006 --tproxy-mark 0x111/0xfff

RUN apt-get update && \
  apt-get install --no-install-recommends -y \
  ca-certificates \
  curl \
  iptables \
  iproute2 \
  iputils-ping \
  knot-dnsutils \
  netcat-openbsd \
  tcpdump \
  conntrack \
  bsdmainutils \
  net-tools \
  lsof \
  sudo \
  && update-ca-certificates \
  && apt-get upgrade -y \
  && apt-get clean \

-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp -i lo -j ACCEPT
-A ISTIO_PRERT -p tcp -m tcp --dport 15008 -m mark ! --mark 0x539/0xfff -j TPROXY --on-port 15008 --tproxy-mark 0x111/0xfff
-A ISTIO_PRERT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A ISTIO_PRERT ! -d 127.0.0.1/32 -p tcp -m mark ! --mark 0x539/0xfff -j TPROXY --on-port 15006 --tproxy-mark 0x111/0xfff

* mangle
-N ISTIO_DROP
-A PREROUTING -m conntrack --ctstate INVALID -j ISTIO_DROP
-A ISTIO_DROP -j DROP
COMMIT
* nat
-N ISTIO_INBOUND
-N ISTIO_REDIRECT
-N ISTIO_IN_REDIRECT
-N ISTIO_OUTPUT
-A ISTIO_INBOUND -p tcp --dport 15008 -j RETURN
-A ISTIO_REDIRECT -p tcp -j REDIRECT --to-ports 15001
-A ISTIO_IN_REDIRECT -p tcp -j REDIRECT --to-ports 15006
-A PREROUTING -p tcp -j ISTIO_INBOUND
-A ISTIO_INBOUND -p tcp --dport 15020 -j RETURN

-A PREROUTING -p tcp -j ISTIO_INBOUND
-A ISTIO_INBOUND -p tcp --dport 15020 -j RETURN
-A ISTIO_INBOUND -p tcp --dport 15021 -j RETURN
-A ISTIO_INBOUND -p tcp --dport 15090 -j RETURN
-A ISTIO_INBOUND -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ISTIO_DIVERT
-A ISTIO_INBOUND -p tcp -j ISTIO_TPROXY
-A PREROUTING -p tcp -m mark --mark 1337 -j CONNMARK --save-mark
-A OUTPUT -p tcp -o lo -m mark --mark 1337 -j RETURN

			"--tproxy-mark", inpodTproxyMark,
		)
		// CLI: -A ISTIO_PRERT -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
		//
		// DESC: Anything that's already in conntrack as an established connection, accept
		iptablesBuilder.AppendRule(
			iptableslog.UndefinedCommand, ChainInpodPrerouting, iptablesconstants.MANGLE,
			"-p", "tcp",
			"-m", "conntrack",
			"--ctstate", "RELATED,ESTABLISHED",
			"-j", "ACCEPT",
		)

-A PREROUTING -p tcp -j ISTIO_INBOUND
-A ISTIO_INBOUND -p tcp --dport 15020 -j RETURN
-A ISTIO_INBOUND -p tcp --dport 15021 -j RETURN
-A ISTIO_INBOUND -p tcp --dport 15090 -j RETURN
-A ISTIO_INBOUND -p tcp -m conntrack --ctstate RELATED,ESTABLISHED -j ISTIO_DIVERT
-A ISTIO_INBOUND -p tcp -j ISTIO_TPROXY
-A PREROUTING -p tcp -m mark --mark 1337 -j CONNMARK --save-mark
-A OUTPUT -p tcp -o lo -m mark --mark 1337 -j RETURN

- Kubeadm: removed preflight check for existence of the conntrack binary, as conntrack is no longer a kube-proxy dependency in version 1.32 and newer. ([#126953](https://github.com/kubernetes/kubernetes/pull/126953), [@aroradaman](https://github.com/aroradaman)) [SIG Cluster Lifecycle]

- `kube-proxy`: Added an option/flag for configuring the `nf_conntrack_tcp_be_liberal` sysctl (in the kernel's netfilter conntrack subsystem).  When enabled, `kube-proxy` will not install the `DROP` rule for invalid conntrack states, which currently breaks users of asymmetric routing. ([#120354](https://github.com/kubernetes/kubernetes/pull/120354), [@aroradaman](https://github.com/aroradaman))

### Feature

github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f h1:KUppIJq7/+SVif2QVs3tOP0zanoHgBEVAwHxUSIzRqU=
github.com/mwitkow/go-conntrack v0.0.0-20190716064945-2f068394615f/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=