{"action":"created","issue":{"url":"https://api.github.com/repos/docker/docker/issues/18108","labels_url":"https://api.github.com/repos/docker/docker/issues/18108/labels{/name}","comments_url":"https://api.github.com/repos/docker/docker/issues/18108/comments","events_url":"https://api.github.com/repos/docker/docker/issues/18108/events","html_url":"https://github.com/docker/docker/pull/18108","id":117947821,"number":18108,"title":"don't try to use default route MTU as container MTU","user":{"login":"phemmer","id":1826947,"avatar_url":"https://avatars.githubusercontent.com/u/1826947?v=3","gravatar_id":"","url":"https://api.github.com/users/phemmer","html_url":"https://github.com/phemmer","followers_url":"https://api.github.com/users/phemmer/followers","following_url":"https://api.github.com/users/phemmer/following{/other_user}","gists_url":"https://api.github.com/users/phemmer/gists{/gist_id}","starred_url":"https://api.github.com/users/phemmer/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/phemmer/subscriptions","organizations_url":"https://api.github.com/users/phemmer/orgs","repos_url":"https://api.github.com/users/phemmer/repos","events_url":"https://api.github.com/users/phemmer/events{/privacy}","received_events_url":"https://api.github.com/users/phemmer/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/docker/docker/labels/status/2-code-review","name":"status/2-code-review","color":"fad8c7"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2015-11-20T01:39:08Z","updated_at":"2015-11-25T05:30:39Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/docker/docker/pulls/18108","html_url":"https://github.com/docker/docker/pull/18108","diff_url":"https://github.com/docker/docker/pull/18108.diff","patch_url":"https://github.com/docker/docker/pull/18108.patch"},"body":"Trying to use the default route's MTU as the container (bridge) MTU is a bad idea:\r\n* The box can have multiple default routes with different MTUs.\r\n* The default route and MTU can change after docker has started.\r\n* Traffic from the container might not even go over the default route (alternate routes, virtual networks, & inter-container communication).\r\n\r\nAside from the issues trying to determine the MTU to use, it's also unnecessary. The kernel performs path MTU discovery to resolve this exact situation. So, this PR lets the kernel do its job.\r\n\r\nIt might even be a good idea to raise the default MTU to 9000. But this PR just fixes the bad behavior. We can improve things in another PR.\r\n\r\ncloses #7796"},"comment":{"url":"https://api.github.com/repos/docker/docker/issues/comments/159495682","html_url":"https://github.com/docker/docker/pull/18108#issuecomment-159495682","issue_url":"https://api.github.com/repos/docker/docker/issues/18108","id":159495682,"user":{"login":"mountkin","id":1496652,"avatar_url":"https://avatars.githubusercontent.com/u/1496652?v=3","gravatar_id":"","url":"https://api.github.com/users/mountkin","html_url":"https://github.com/mountkin","followers_url":"https://api.github.com/users/mountkin/followers","following_url":"https://api.github.com/users/mountkin/following{/other_user}","gists_url":"https://api.github.com/users/mountkin/gists{/gist_id}","starred_url":"https://api.github.com/users/mountkin/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mountkin/subscriptions","organizations_url":"https://api.github.com/users/mountkin/orgs","repos_url":"https://api.github.com/users/mountkin/repos","events_url":"https://api.github.com/users/mountkin/events{/privacy}","received_events_url":"https://api.github.com/users/mountkin/received_events","type":"User","site_admin":false},"created_at":"2015-11-25T05:30:39Z","updated_at":"2015-11-25T05:30:39Z","body":"@phemmer PTAL https://github.com/docker/docker/issues/13475"}}