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Cypher-shell connection timed out on Linux terminal

9mikev
Node Link

I'm setting up neo4j server on Ubunti 18.04 LTS, and after I installed it following the instructions here, the cypher-shell command does not work. It does nothing, and after some time it prints out

connection timed out: /127.0.0.1:7687

neo4j status prints

Neo4j is running at pid 45437

and if I check ports in use with sudo ss -tunlp it prints

Netid     State        Recv-Q       Send-Q                   Local Address:Port              Peer Address:Port
...
tcp       LISTEN       0            128                 [::ffff:127.0.0.1]:7687                         *:*          users:(("java",pid=45437,fd=280))
...
tcp       LISTEN       0            50                  [::ffff:127.0.0.1]:7474                         *:*          users:(("java",pid=45437,fd=281))
...

Here is my configuration file

#*****************************************************************
# Neo4j configuration
#
# For more details and a complete list of settings, please see
# https://neo4j.com/docs/operations-manual/current/reference/configuration-settings/
#*****************************************************************

# The name of the default database
#dbms.default_database=neo4j

# Paths of directories in the installation.
dbms.directories.data=/var/lib/neo4j/data
dbms.directories.plugins=/var/lib/neo4j/plugins
dbms.directories.logs=/var/log/neo4j
dbms.directories.lib=/usr/share/neo4j/lib
#dbms.directories.run=run
#dbms.directories.licenses=licenses
#dbms.directories.transaction.logs.root=data/transactions

# This setting constrains all `LOAD CSV` import files to be under the `import` directory. Remove or comment it out to
# allow files to be loaded from anywhere in the filesystem; this introduces possible security problems. See the
# `LOAD CSV` section of the manual for details.
dbms.directories.import=/var/lib/neo4j/import

# Whether requests to Neo4j are authenticated.
# To disable authentication, uncomment this line
#dbms.security.auth_enabled=false

# Enable this to be able to upgrade a store from an older version.
#dbms.allow_upgrade=true

#********************************************************************
# Memory Settings
#********************************************************************
#
# Memory settings are specified kilobytes with the 'k' suffix, megabytes with
# 'm' and gigabytes with 'g'.
# If Neo4j is running on a dedicated server, then it is generally recommended
# to leave about 2-4 gigabytes for the operating system, give the JVM enough
# heap to hold all your transaction state and query context, and then leave the
# rest for the page cache.

# Java Heap Size: by default the Java heap size is dynamically calculated based
# on available system resources. Uncomment these lines to set specific initial
# and maximum heap size.
#dbms.memory.heap.initial_size=512m
#dbms.memory.heap.max_size=512m

# The amount of memory to use for mapping the store files.
# The default page cache memory assumes the machine is dedicated to running
# Neo4j, and is heuristically set to 50% of RAM minus the Java heap size.
#dbms.memory.pagecache.size=10g

# Limit the amount of memory that all of the running transaction can consume.
# By default there is no limit.
#dbms.memory.transaction.global_max_size=256m

# Limit the amount of memory that a single transaction can consume.
# By default there is no limit.
#dbms.memory.transaction.max_size=16m

# Transaction state location. It is recommended to use ON_HEAP.
dbms.tx_state.memory_allocation=ON_HEAP

#*****************************************************************
# Network connector configuration
#*****************************************************************

# With default configuration Neo4j only accepts local connections.
# To accept non-local connections, uncomment this line:
#dbms.default_listen_address=0.0.0.0

# You can also choose a specific network interface, and configure a non-default
# port for each connector, by setting their individual listen_address.

# The address at which this server can be reached by its clients. This may be the server's IP address or DNS name, or
# it may be the address of a reverse proxy which sits in front of the server. This setting may be overridden for
# individual connectors below.
#dbms.default_advertised_address=localhost

# You can also choose a specific advertised hostname or IP address, and
# configure an advertised port for each connector, by setting their
# individual advertised_address.

# By default, encryption is turned off.
# To turn on encryption, an ssl policy for the connector needs to be configured
# Read more in SSL policy section in this file for how to define a SSL policy.

# Bolt connector
dbms.connector.bolt.enabled=true
dbms.connector.bolt.tls_level=DISABLED
dbms.connector.bolt.listen_address=:7687
dbms.connector.bolt.advertised_address=:7687

# HTTP Connector. There can be zero or one HTTP connectors.
dbms.connector.http.enabled=true
dbms.connector.http.listen_address=:7474
dbms.connector.http.advertised_address=:7474

# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=false
dbms.connector.https.listen_address=:7473
dbms.connector.https.advertised_address=:7473

# Number of Neo4j worker threads.
#dbms.threads.worker_count=

#*****************************************************************
# SSL policy configuration
#*****************************************************************

# Each policy is configured under a separate namespace, e.g.
#    dbms.ssl.policy.<scope>.*
#    <scope> can be any of 'bolt', 'https', 'cluster' or 'backup'
#
# The scope is the name of the component where the policy will be used
# Each component where the use of an ssl policy is desired needs to declare at least one setting of the policy.
# Allowable values are 'bolt', 'https', 'cluster' or 'backup'.

# E.g if bolt and https connectors should use the same policy, the following could be declared
#   dbms.ssl.policy.bolt.base_directory=certificates/default
#   dbms.ssl.policy.https.base_directory=certificates/default
# However, it's strongly encouraged to not use the same key pair for multiple scopes.
#
# N.B: Note that a connector must be configured to support/require
#      SSL/TLS for the policy to actually be utilized.
#
# see: dbms.connector.*.tls_level

# SSL settings (dbms.ssl.policy.<scope>.*)
#  .base_directory       Base directory for SSL policies paths. All relative paths within the
#                        SSL configuration will be resolved from the base dir.
#
#  .private_key          A path to the key file relative to the '.base_directory'.
#
#  .private_key_password The password for the private key.
#
#  .public_certificate   A path to the public certificate file relative to the '.base_directory'.
#
#  .trusted_dir          A path to a directory containing trusted certificates.
#
#  .revoked_dir          Path to the directory with Certificate Revocation Lists (CRLs).
#
#  .verify_hostname      If true, the server will verify the hostname that the client uses to connect with. In order
#                        for this to work, the server public certificate must have a valid CN and/or matching
#                        Subject Alternative Names.
#
#  .client_auth          How the client should be authorized. Possible values are: 'none', 'optional', 'require'.
#
#  .tls_versions         A comma-separated list of allowed TLS versions. By default only TLSv1.2 is allowed.
#
#  .trust_all            Setting this to 'true' will ignore the trust truststore, trusting all clients and servers.
#                        Use of this mode is discouraged. It would offer encryption but no security.
#
#  .ciphers              A comma-separated list of allowed ciphers. The default ciphers are the defaults of
#                        the JVM platform.

# Bolt SSL configuration
#dbms.ssl.policy.bolt.enabled=true
#dbms.ssl.policy.bolt.base_directory=certificates/bolt
#dbms.ssl.policy.bolt.private_key=private.key
#dbms.ssl.policy.bolt.public_certificate=public.crt
#dbms.ssl.policy.bolt.client_auth=NONE

# Https SSL configuration
#dbms.ssl.policy.https.enabled=true
#dbms.ssl.policy.https.base_directory=certificates/https
#dbms.ssl.policy.https.private_key=private.key
#dbms.ssl.policy.https.public_certificate=public.crt
#dbms.ssl.policy.https.client_auth=NONE

# Cluster SSL configuration
#dbms.ssl.policy.cluster.enabled=true
#dbms.ssl.policy.cluster.base_directory=certificates/cluster
#dbms.ssl.policy.cluster.private_key=private.key
#dbms.ssl.policy.cluster.public_certificate=public.crt

# Backup SSL configuration
#dbms.ssl.policy.backup.enabled=true
#dbms.ssl.policy.backup.base_directory=certificates/backup
#dbms.ssl.policy.backup.private_key=private.key
#dbms.ssl.policy.backup.public_certificate=public.crt

#*****************************************************************
# Logging configuration
#*****************************************************************

# To enable HTTP logging, uncomment this line
#dbms.logs.http.enabled=true

# Number of HTTP logs to keep.
#dbms.logs.http.rotation.keep_number=5

# Size of each HTTP log that is kept.
#dbms.logs.http.rotation.size=20m

# To enable GC Logging, uncomment this line
#dbms.logs.gc.enabled=true

# GC Logging Options
# see https://docs.oracle.com/en/java/javase/11/tools/java.html#GUID-BE93ABDC-999C-4CB5-A88B-1994AAAC74D5
#dbms.logs.gc.options=-Xlog:gc*,safepoint,age*=trace

# Number of GC logs to keep.
#dbms.logs.gc.rotation.keep_number=5

# Size of each GC log that is kept.
#dbms.logs.gc.rotation.size=20m

# Log level for the debug log. One of DEBUG, INFO, WARN and ERROR. Be aware that logging at DEBUG level can be very verbose.
#dbms.logs.debug.level=INFO

# Size threshold for rotation of the debug log. If set to zero then no rotation will occur. Accepts a binary suffix "k",
# "m" or "g".
#dbms.logs.debug.rotation.size=20m

# Maximum number of history files for the internal log.
#dbms.logs.debug.rotation.keep_number=7

#*****************************************************************
# Miscellaneous configuration
#*****************************************************************

# Enable this to specify a parser other than the default one.
#cypher.default_language_version=3.5

# Determines if Cypher will allow using file URLs when loading data using
# `LOAD CSV`. Setting this value to `false` will cause Neo4j to fail `LOAD CSV`
# clauses that load data from the file system.
#dbms.security.allow_csv_import_from_file_urls=true


# Value of the Access-Control-Allow-Origin header sent over any HTTP or HTTPS
# connector. This defaults to '*', which allows broadest compatibility. Note
# that any URI provided here limits HTTP/HTTPS access to that URI only.
#dbms.security.http_access_control_allow_origin=*

# Value of the HTTP Strict-Transport-Security (HSTS) response header. This header
# tells browsers that a webpage should only be accessed using HTTPS instead of HTTP.
# It is attached to every HTTPS response. Setting is not set by default so
# 'Strict-Transport-Security' header is not sent. Value is expected to contain
# directives like 'max-age', 'includeSubDomains' and 'preload'.
#dbms.security.http_strict_transport_security=

# Retention policy for transaction logs needed to perform recovery and backups.
dbms.tx_log.rotation.retention_policy=1 days

# Only allow read operations from this Neo4j instance. This mode still requires
# write access to the directory for lock purposes.
#dbms.read_only=false

# Comma separated list of JAX-RS packages containing JAX-RS resources, one
# package name for each mountpoint. The listed package names will be loaded
# under the mountpoints specified. Uncomment this line to mount the
# org.neo4j.examples.server.unmanaged.HelloWorldResource.java from
# neo4j-server-examples under /examples/unmanaged, resulting in a final URL of
# http://localhost:7474/examples/unmanaged/helloworld/{nodeId}
#dbms.unmanaged_extension_classes=org.neo4j.examples.server.unmanaged=/examples/unmanaged

# A comma separated list of procedures and user defined functions that are allowed
# full access to the database through unsupported/insecure internal APIs.
#dbms.security.procedures.unrestricted=my.extensions.example,my.procedures.*

# A comma separated list of procedures to be loaded by default.
# Leaving this unconfigured will load all procedures found.
#dbms.security.procedures.allowlist=apoc.coll.*,apoc.load.*,gds.*

#********************************************************************
# JVM Parameters
#********************************************************************

# G1GC generally strikes a good balance between throughput and tail
# latency, without too much tuning.
dbms.jvm.additional=-XX:+UseG1GC

# Have common exceptions keep producing stack traces, so they can be
# debugged regardless of how often logs are rotated.
dbms.jvm.additional=-XX:-OmitStackTraceInFastThrow

# Make sure that `initmemory` is not only allocated, but committed to
# the process, before starting the database. This reduces memory
# fragmentation, increasing the effectiveness of transparent huge
# pages. It also reduces the possibility of seeing performance drop
# due to heap-growing GC events, where a decrease in available page
# cache leads to an increase in mean IO response time.
# Try reducing the heap memory, if this flag degrades performance.
dbms.jvm.additional=-XX:+AlwaysPreTouch

# Trust that non-static final fields are really final.
# This allows more optimizations and improves overall performance.
# NOTE: Disable this if you use embedded mode, or have extensions or dependencies that may use reflection or
# serialization to change the value of final fields!
dbms.jvm.additional=-XX:+UnlockExperimentalVMOptions
dbms.jvm.additional=-XX:+TrustFinalNonStaticFields

# Disable explicit garbage collection, which is occasionally invoked by the JDK itself.
dbms.jvm.additional=-XX:+DisableExplicitGC

#Increase maximum number of nested calls that can be inlined from 9 (default) to 15
dbms.jvm.additional=-XX:MaxInlineLevel=15

# Disable biased locking
dbms.jvm.additional=-XX:-UseBiasedLocking

# Restrict size of cached JDK buffers to 256 KB
dbms.jvm.additional=-Djdk.nio.maxCachedBufferSize=262144

# More efficient buffer allocation in Netty by allowing direct no cleaner buffers.
dbms.jvm.additional=-Dio.netty.tryReflectionSetAccessible=true

# Exits JVM on the first occurrence of an out-of-memory error. Its preferable to restart VM in case of out of memory errors.
# dbms.jvm.additional=-XX:+ExitOnOutOfMemoryError

# Expand Diffie Hellman (DH) key size from default 1024 to 2048 for DH-RSA cipher suites used in server TLS handshakes.
# This is to protect the server from any potential passive eavesdropping.
dbms.jvm.additional=-Djdk.tls.ephemeralDHKeySize=2048

# This mitigates a DDoS vector.
dbms.jvm.additional=-Djdk.tls.rejectClientInitiatedRenegotiation=true

# Enable remote debugging
#dbms.jvm.additional=-agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=*:5005

# This filter prevents deserialization of arbitrary objects via java object serialization, addressing potential vulnerabilities.
# By default this filter whitelists all neo4j classes, as well as classes from the hazelcast library and the java standard library.
# These defaults should only be modified by expert users!
# For more details (including filter syntax) see: https://openjdk.java.net/jeps/290
#dbms.jvm.additional=-Djdk.serialFilter=java.**;org.neo4j.**;com.neo4j.**;com.hazelcast.**;net.sf.ehcache.Element;com.sun.proxy.*;org.openjdk.jmh.**;!*

# Increase the default flight recorder stack sampling depth from 64 to 256, to avoid truncating frames when profiling.
dbms.jvm.additional=-XX:FlightRecorderOptions=stackdepth=256

# Allow profilers to sample between safepoints. Without this, sampling profilers may produce less accurate results.
dbms.jvm.additional=-XX:+UnlockDiagnosticVMOptions
dbms.jvm.additional=-XX:+DebugNonSafepoints

# Disable logging JMX endpoint.
dbms.jvm.additional=-Dlog4j2.disable.jmx=true

# Limit JVM metaspace and code cache to allow garbage collection. Used by cypher for code generation and may grow indefinitely unless constrained.
# Useful for memory constrained environments
#dbms.jvm.additional=-XX:MaxMetaspaceSize=1024m
#dbms.jvm.additional=-XX:ReservedCodeCacheSize=512m

#********************************************************************
# Wrapper Windows NT/2000/XP Service Properties
#********************************************************************
# WARNING - Do not modify any of these properties when an application
#  using this configuration file has been installed as a service.
#  Please uninstall the service before modifying this section.  The
#  service can then be reinstalled.

# Name of the service
dbms.windows_service_name=neo4j

#********************************************************************
# Other Neo4j system properties
#********************************************************************

Any help would appreciated!

1 ACCEPTED SOLUTION

@9mikev
do you have iptables/firewall in between which is rejecting the connection

what is the result of

 (echo > "/dev/tcp/127.0.0.1/7678") >/dev/null 2>&1 && echo "CAN CONNECT" || echo "CANNOT CONNECT"

View solution in original post

4 REPLIES 4

david_allen
Neo4j
Neo4j

I'm not 100% sure what's going on but I think this is the issue right here.

This should be set to 0.0.0.0:7687 -- it needs an IP and the special reserved 0.0.0.0 indicates to listen on all network devices. Worth a quicky try.

Documentation reference: Configure connectors - Operations Manual

Thank you, but that did not fix the problem. Same thing happens again.

I guess the server is up and listening to the ports as seen in the ss -tunlp command, but for some reason cypher-shell can't connect to it...

@9mikev
do you have iptables/firewall in between which is rejecting the connection

what is the result of

 (echo > "/dev/tcp/127.0.0.1/7678") >/dev/null 2>&1 && echo "CAN CONNECT" || echo "CANNOT CONNECT"

@dana.canzano

The command you suggested takes some time before printing anything and eventually prints 'cannot connect'.

Turns out the iptables rules were rejecting the connection as you said. I changed them to allow loopback connections and now it works fine.

Thank you!

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