Two JDK8 IPv6 failures on containers on dockerhost-azure x64 systems

The two test cases listed below from `jdk_net` fail consistently on containers on these machines: https://ci.adoptium.net/label/hw.dockerhost.dockerhost-azure-ubuntu2204-x64-1/ - Note that this is specific to JDK8 - later versions pass the tests on test-docker-ubuntu2404-x64-1

Please set the title to indicate the test name and machine name where known.

To make it easy for the infrastructure team to repeat and diagnose, please
answer the following questions:

- test suite/name (e.g, BUILD_LIST, TARGET, CUSTOM_TARGET)? - : [java/net/ipv6tests/B6521014.java.B6521014](https://ci.adoptium.net/job/Test_openjdk8_hs_extended.openjdk_x86-64_linux/252/testReport/java_net_ipv6tests_B6521014/java/B6521014/)
- [java/net/Inet6Address/B6206527.java.B6206527](https://ci.adoptium.net/job/Test_openjdk8_hs_extended.openjdk_x86-64_linux/252/testReport/java_net_Inet6Address_B6206527/java/B6206527_2/)
- a link into recent `Test_` job on https://ci.adoptium.net which showed the failure https://ci.adoptium.net/job/Test_openjdk8_hs_extended.openjdk_x86-64_linux/252/testReport plus various links in the notes at the bottom of https://github.com/adoptium/infrastructure/issues/3868#issuecomment-3227682265
- **Hyperlink** to re-run in Grinder: [Link to re-grind - set LABEL accordingly](https://ci.adoptium.net/job/Grinder/parambuild/?SDK_RESOURCE=nightly&TARGET=jdk_custom&TEST_FLAG=&UPSTREAM_TEST_JOB_NAME=&DOCKER_REQUIRED=false&ACTIVE_NODE_TIMEOUT=&VENDOR_TEST_DIRS=&EXTRA_DOCKER_ARGS=&TKG_OWNER_BRANCH=adoptium%3Amaster&OPENJ9_SYSTEMTEST_OWNER_BRANCH=eclipse%3Amaster&PLATFORM=x86-64_linux&GENERATE_JOBS=false&KEEP_REPORTDIR=true&PERSONAL_BUILD=false&ADOPTOPENJDK_REPO=https%3A%2F%2Fgithub.com%2Fsxa%2Faqa-tests.git&RERUN_ITERATIONS=0&LABEL=&EXTRA_OPTIONS=&CUSTOMIZED_SDK_URL=&BUILD_IDENTIFIER=&ADOPTOPENJDK_BRANCH=wayland_detect&LIGHT_WEIGHT_CHECKOUT=false&NON_AQA_TEST_REPOS=&USE_JRE=false&ARTIFACTORY_SERVER=&KEEP_WORKSPACE=false&USER_CREDENTIALS_ID=&JDK_VERSION=8&ITERATIONS=10&VENDOR_TEST_REPOS=&JDK_REPO=&OPENJ9_BRANCH=master&OPENJ9_SHA=&JCK_GIT_REPO=&VENDOR_TEST_BRANCHES=&OPENJ9_REPO=https%3A%2F%2Fgithub.com%2Feclipse-openj9%2Fopenj9.git&UPSTREAM_JOB_NAME=&CLOUD_PROVIDER=&PLATFORM_AND_MACHINE=&CUSTOM_TARGET=java%2Fnet%2Fipv6tests%2FB6521014.java+java%2Fnet%2FInet6Address%2FB6206527.java+java%2Fnet%2FInet6Address%2FB6206527.java+java%2Fnet%2Fipv6tests%2FB6521014.java&VENDOR_TEST_SHAS=&JDK_BRANCH=&TEST_IMAGES_REQUIRED=true&LABEL_ADDITION=&ARTIFACTORY_REPO=&ARTIFACTORY_ROOT_DIR=&UPSTREAM_TEST_JOB_NUMBER=&DOCKERIMAGE_TAG=&JDK_IMPL=hotspot&TEST_TIME=&SSH_AGENT_CREDENTIAL=&AUTO_DETECT=true&SLACK_CHANNEL=aqavit-bot&DYNAMIC_COMPILE=false&ADOPTOPENJDK_SYSTEMTEST_OWNER_BRANCH=adoptium%3Amaster&APPLICATION_OPTIONS=&CUSTOMIZED_SDK_URL_CREDENTIAL_ID=eclipse_temurin_bot_email_and_token&ARCHIVE_TEST_RESULTS=false&OPENJDK_SHA=&NUM_MACHINES=1&RERUN_FAILURE=false&BUILD_LIST=openjdk&USE_TESTENV_PROPERTIES=true&UPSTREAM_JOB_NUMBER=&STF_OWNER_BRANCH=adoptium%3Amaster&TIME_LIMIT=10&JVM_OPTIONS=&PARALLEL=None)
- Is there an existing issue elsewhere covering this?
- Which machine(s) does it work on? Anything that isn't an azure dockerhost
- Which machine(s) does it fail on? azure dockerhost containers

Any other details:
Could be related to the networking on that host using NAT to access the internet?

Start by rerunning the two named JDK8 tests, java/net/ipv6tests/B6521014.java.B6521014 and java/net/Inet6Address/B6206527.java.B6206527, through the linked Grinder configuration or Test_openjdk8_hs_extended.openjdk_x86-64_linux/252. Compare Azure dockerhost containers with a non-Azure machine, then use the job reports and infrastructure issue 3868 notes to identify and document the networking cause or required infrastructure change.

Written by the indexing model from the issue text.