# SYN packets retransmitted sometimes **URL:** \ **Category:** General\ **Tags:** docker\ **Created:** [September 5, 2019, 6:00pm UTC](https://forums.docker.com/t/syn-packets-retransmitted-sometimes/80790 "2019-09-05T18:00:29Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![yunusz](https://avatars.discourse-cdn.com/v4/letter/y/d2c977/32.png) [@yunusz](https://forums.docker.com/u/yunusz)\ **Post date:** [September 5, 2019, 6:00pm UTC](https://forums.docker.com/t/syn-packets-retransmitted-sometimes/80790/1 "2019-09-05T18:00:29Z")
Hi guys! I have a network related issues. I have a container running gunicorn app, with port 8000 published. I’m use `echo 'exit' | telnet 172.31.3.10 8000` to connect to this port, from my laptop. Docker host has ip 172.31.3.10, my laptop is 172.31.3.246, both connected by wire to that LAN. What I see is a pretty big time for telnet to establish connection, sometimes, but sometimes not. I’ve looked a little deeper and wireshark showed me SYN packets re-transmitted in such cases. I have dumps from laptop and host, for both cases: with and without SYN re-transmission, here is one of it: - docker host, SYN re-transmission ![docker-host%5Bwrong%5D](https://global.discourse-cdn.com/docker/original/3X/0/7/07250404ebb977c97735da64d54f6871adb5e8cd.png) > **OS version** > > ```auto > $ uname -a > Linux remy-base-1 4.15.0-58-generic #64~16.04.1-Ubuntu SMP Wed Aug 7 14:10:35 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux > > $ cat /etc/*elease > DISTRIB_ID=Ubuntu > DISTRIB_RELEASE=16.04 > DISTRIB_CODENAME=xenial > DISTRIB_DESCRIPTION="Ubuntu 16.04.6 LTS" > NAME="Ubuntu" > VERSION="16.04.6 LTS (Xenial Xerus)" > ID=ubuntu > ID_LIKE=debian > PRETTY_NAME="Ubuntu 16.04.6 LTS" > VERSION_ID="16.04" > HOME_URL="http://www.ubuntu.com/" > SUPPORT_URL="http://help.ubuntu.com/" > BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/" > VERSION_CODENAME=xenial > UBUNTU_CODENAME=xenial > > $ sudo ufw status > Status: inactive > > ``` > **Docker version** > > ```auto > $ docker version > Client: > Version: 18.09.5 > API version: 1.39 > Go version: go1.10.8 > Git commit: e8ff056 > Built: Thu Apr 11 04:44:24 2019 > OS/Arch: linux/amd64 > Experimental: false > > Server: Docker Engine - Community > Engine: > Version: 18.09.5 > API version: 1.39 (minimum version 1.12) > Go version: go1.10.8 > Git commit: e8ff056 > Built: Thu Apr 11 04:10:53 2019 > OS/Arch: linux/amd64 > Experimental: false > > $ docker system info > Containers: 5 > Running: 5 > Paused: 0 > Stopped: 0 > Images: 145 > Server Version: 18.09.5 > Storage Driver: overlay2 > Backing Filesystem: extfs > Supports d_type: true > Native Overlay Diff: true > Logging Driver: json-file > Cgroup Driver: cgroupfs > Plugins: > Volume: local > Network: bridge host macvlan null overlay > Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog > Swarm: inactive > Runtimes: nvidia runc > Default Runtime: runc > Init Binary: docker-init > containerd version: bb71b10fd8f58240ca47fbb579b9d1028eea7c84 > runc version: 2b18fe1d885ee5083ef9f0838fee39b62d653e30 > init version: fec3683 > Security Options: > apparmor > seccomp > Profile: default > Kernel Version: 4.15.0-58-generic > Operating System: Ubuntu 16.04.6 LTS > OSType: linux > Architecture: x86_64 > CPUs: 12 > Total Memory: 15.58GiB > Name: remy-base-1 > ID: YC2W:NOUT:FD7R:4E54:CS2P:Y6JE:EI35:BZDA:BRL6:PXPJ:E43O:YOQS > Docker Root Dir: /var/lib/docker > Debug Mode (client): false > Debug Mode (server): false > Registry: https://index.docker.io/v1/ > Labels: > Experimental: false > Insecure Registries: > 127.0.0.0/8 > Live Restore Enabled: false > Product License: Community Engine > > WARNING: No swap limit support > > ``` > **My container** > > ```auto > $ docker inspect controllers_service > [ > { > "Id": "d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355", > "Created": "2019-08-14T15:21:25.77887618Z", > "Path": "gunicorn", > "Args": [ > "-c", > "config.py", > "controllers:app" > ], > "State": { > "Status": "running", > "Running": true, > "Paused": false, > "Restarting": false, > "OOMKilled": false, > "Dead": false, > "Pid": 3726, > "ExitCode": 0, > "Error": "", > "StartedAt": "2019-09-04T07:46:50.304673906Z", > "FinishedAt": "2019-09-04T10:46:48.1642967+03:00" > }, > "Image": "sha256:954a51ab10b535b797ce27a04dd1963170db4f6a44f26f0d1869865b0669ee9d", > "ResolvConfPath": "/var/lib/docker/containers/d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355/resolv.conf", > "HostnamePath": "/var/lib/docker/containers/d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355/hostname", > "HostsPath": "/var/lib/docker/containers/d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355/hosts", > "LogPath": "/var/lib/docker/containers/d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355/d1bd7eb9537b6c534dd384b33ff33d072687fdb6b11821dfc5fc7f6f4c588355-json.log", > "Name": "/controllers_service", > "RestartCount": 0, > "Driver": "overlay2", > "Platform": "linux", > "MountLabel": "", > "ProcessLabel": "", > "AppArmorProfile": "unconfined", > "ExecIDs": null, > "HostConfig": { > "Binds": [ > "/dev:/dev" > ], > "ContainerIDFile": "", > "LogConfig": { > "Type": "json-file", > "Config": {} > }, > "NetworkMode": "bridge", > "PortBindings": { > "8000/tcp": [ > { > "HostIp": "", > "HostPort": "8000" > } > ] > }, > "RestartPolicy": { > "Name": "unless-stopped", > "MaximumRetryCount": 0 > }, > "AutoRemove": false, > "VolumeDriver": "", > "VolumesFrom": null, > "CapAdd": [ > "AUDIT_WRITE", > "CHOWN", > "DAC_OVERRIDE", > "FOWNER", > "FSETID", > "KILL", > "MKNOD", > "NET_BIND_SERVICE", > "NET_RAW", > "SETFCAP", > "SETGID", > "SETPCAP", > "SETUID", > "SYS_CHROOT" > ], > "CapDrop": [ > "AUDIT_CONTROL", > "BLOCK_SUSPEND", > "DAC_READ_SEARCH", > "IPC_LOCK", > "IPC_OWNER", > "LEASE", > "LINUX_IMMUTABLE", > "MAC_ADMIN", > "MAC_OVERRIDE", > "NET_ADMIN", > "NET_BROADCAST", > "SYSLOG", > "SYS_ADMIN", > "SYS_BOOT", > "SYS_MODULE", > "SYS_NICE", > "SYS_PACCT", > "SYS_PTRACE", > "SYS_RAWIO", > "SYS_RESOURCE", > "SYS_TIME", > "SYS_TTY_CONFIG", > "WAKE_ALARM" > ], > "Dns": [], > "DnsOptions": [], > "DnsSearch": [], > "ExtraHosts": [], > "GroupAdd": null, > "IpcMode": "shareable", > "Cgroup": "", > "Links": null, > "OomScoreAdj": 0, > "PidMode": "", > "Privileged": true, > "PublishAllPorts": false, > "ReadonlyRootfs": false, > "SecurityOpt": [ > "label=disable" > ], > "UTSMode": "", > "UsernsMode": "", > "ShmSize": 67108864, > "Runtime": "runc", > "ConsoleSize": [ > 0, > 0 > ], > "Isolation": "", > "CpuShares": 0, > "Memory": 1073741824, > "NanoCpus": 3000000000, > "CgroupParent": "", > "BlkioWeight": 0, > "BlkioWeightDevice": null, > "BlkioDeviceReadBps": null, > "BlkioDeviceWriteBps": null, > "BlkioDeviceReadIOps": null, > "BlkioDeviceWriteIOps": null, > "CpuPeriod": 0, > "CpuQuota": 0, > "CpuRealtimePeriod": 0, > "CpuRealtimeRuntime": 0, > "CpusetCpus": "", > "CpusetMems": "", > "Devices": [], > "DeviceCgroupRules": null, > "DiskQuota": 0, > "KernelMemory": 0, > "MemoryReservation": 536870912, > "MemorySwap": -1, > "MemorySwappiness": null, > "OomKillDisable": false, > "PidsLimit": 0, > "Ulimits": null, > "CpuCount": 0, > "CpuPercent": 0, > "IOMaximumIOps": 0, > "IOMaximumBandwidth": 0, > "MaskedPaths": null, > "ReadonlyPaths": null > }, > "GraphDriver": { > "Data": { > "LowerDir": "/var/lib/docker/overlay2/2d61fa4bdcd60acebbaff47dbe60ed2013226b15bbcd779b5cabcb20b1c6ee89-init/diff:/var/lib/docker/overlay2/8414fa036dc668a031f32eabd00453ca2ee6582042dab3c71fd412438086db26/diff:/var/lib/docker/overlay2/c6f56b6a1d8b6eb2951278989c275c5a112c4c9cb85c95a4cf4a51cab723e3f9/diff:/var/lib/docker/overlay2/5f6307eac7e35d0e23b023999df51dd7d827b02b6ef258621c694da0d1eacd8e/diff:/var/lib/docker/overlay2/2dca0e566480a1d498941d28d8d2dcf1f02d7df069e5276bd19a4348d9dfdd27/diff:/var/lib/docker/overlay2/c09e3fcb3199d7a6dea9614f4be958afe4e238e93d79a693bc45140f89a23e7b/diff:/var/lib/docker/overlay2/cdd192d528150e6f2d9879ce3247f08f839680b375ed1319dab2c7d7ac1268e8/diff:/var/lib/docker/overlay2/934e930253feeb6bbc4af2980b568ef2898eee7217ee05c43a4de3df34799171/diff", > "MergedDir": "/var/lib/docker/overlay2/2d61fa4bdcd60acebbaff47dbe60ed2013226b15bbcd779b5cabcb20b1c6ee89/merged", > "UpperDir": "/var/lib/docker/overlay2/2d61fa4bdcd60acebbaff47dbe60ed2013226b15bbcd779b5cabcb20b1c6ee89/diff", > "WorkDir": "/var/lib/docker/overlay2/2d61fa4bdcd60acebbaff47dbe60ed2013226b15bbcd779b5cabcb20b1c6ee89/work" > }, > "Name": "overlay2" > }, > "Mounts": [ > { > "Type": "bind", > "Source": "/dev", > "Destination": "/dev", > "Mode": "", > "RW": true, > "Propagation": "rprivate" > } > ], > "Config": { > "Hostname": "1dc4badbefe3", > "Domainname": "", > "User": "", > "AttachStdin": false, > "AttachStdout": false, > "AttachStderr": false, > "ExposedPorts": { > "8000/tcp": {} > }, > "Tty": false, > "OpenStdin": false, > "StdinOnce": false, > "Env": [ > "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", > "PYTHONPATH=/" > ], > "Cmd": [], > "ArgsEscaped": true, > "Image": "controllers_service:0.2.0", > "Volumes": { > "/dev": {} > }, > "WorkingDir": "/", > "Entrypoint": [ > "gunicorn", > "-c", > "config.py", > "dispensers:app" > ], > "MacAddress": "02:42:ac:11:00:02", > "OnBuild": null, > "Labels": {} > }, > "NetworkSettings": { > "Bridge": "", > "SandboxID": "51e4c73e9e8586b36007acf4e7dc68f369191f4e5f8c838b47cbb0774ef9726a", > "HairpinMode": false, > "LinkLocalIPv6Address": "", > "LinkLocalIPv6PrefixLen": 0, > "Ports": { > "8000/tcp": [ > { > "HostIp": "0.0.0.0", > "HostPort": "8000" > } > ] > }, > "SandboxKey": "/var/run/docker/netns/51e4c73e9e85", > "SecondaryIPAddresses": null, > "SecondaryIPv6Addresses": null, > "EndpointID": "d23ea731f678708dc67b23754a19d8a6a791995e94c254f69e142c5001f0af07", > "Gateway": "172.17.0.1", > "GlobalIPv6Address": "", > "GlobalIPv6PrefixLen": 0, > "IPAddress": "172.17.0.3", > "IPPrefixLen": 16, > "IPv6Gateway": "", > "MacAddress": "02:42:ac:11:00:02", > "Networks": { > "bridge": { > "IPAMConfig": {}, > "Links": null, > "Aliases": null, > "NetworkID": "7d7e76a89e2fae4ba1cec2118119c1c803cbf5a557f5a780c8c7a87084716861", > "EndpointID": "d23ea731f678708dc67b23754a19d8a6a791995e94c254f69e142c5001f0af07", > "Gateway": "172.17.0.1", > "IPAddress": "172.17.0.3", > "IPPrefixLen": 16, > "IPv6Gateway": "", > "GlobalIPv6Address": "", > "GlobalIPv6PrefixLen": 0, > "MacAddress": "02:42:ac:11:00:02", > "DriverOpts": null > } > } > } > } > ] > > ``` I’ve tried to search similar issues, but found only two: - [https://tech.xing.com/a-reason-for-unexplained-connection-timeouts-on-kubernetes-docker-abd041cf7e02](https://tech.xing.com/a-reason-for-unexplained-connection-timeouts-on-kubernetes-docker-abd041cf7e02) - [https://tech.vijayp.ca/linux-kernel-bug-delivers-corrupt-tcp-ip-data-to-mesos-kubernetes-docker-containers-4986f88f7a19](https://tech.vijayp.ca/linux-kernel-bug-delivers-corrupt-tcp-ip-data-to-mesos-kubernetes-docker-containers-4986f88f7a19) but not sure, is it relevant to my case. Please, help me with investigating and fixing it Thanks a lot!