public Builder setIpProtocol(java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      ipProtocol_ = value;
      bitField0_ |= 0x00000040;
      onChanged();
      return this;
    }
<pre>
The IP protocol to which the external access rule applies. This value can
be one of the following three protocol strings (not case-sensitive):
`tcp`, `udp`, or `icmp`.
</pre>

<code>string ip_protocol = 8;</code>

@param value The ipProtocol to set.
@return This builder for chaining.
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/ExternalAccessRule.java