In tcpdump, which is the difference between the following two commands? I tried to understand but they seems pretty much the same to me.
tcpdump ip host google.com
and
tcpdump ip and host google.com
There is no difference. If you compare the packet-matching code, generated by including the -d option, then you can see that they produce identical results:
tcpdump -d "ip host google.com"
(000) ldh [12]
(001) jeq #0x800 jt 2 jf 7
(002) ld [26]
(003) jeq #0x8efa41ae jt 6 jf 4
(004) ld [30]
(005) jeq #0x8efa41ae jt 6 jf 7
(006) ret #262144
(007) ret #0
tcpdump -d "ip and host google.com"
(000) ldh [12]
(001) jeq #0x800 jt 2 jf 7
(002) ld [26]
(003) jeq #0x8efa41ae jt 6 jf 4
(004) ld [30]
(005) jeq #0x8efa41ae jt 6 jf 7
(006) ret #262144
(007) ret #0
Related
Please do as i do in your vps and then maybe the issue reproduced,replace the variable $vps_ip with your real vps ip during the below steps.
wget https://saimei.ftp.acc.umu.se/debian-cd/current/amd64/iso-cd/debian-10.4.0-amd64-netinst.iso
transmission-create -o debian.torrent debian-10.4.0-amd64-netinst.iso
Create a trackerless torrent ,show info on it:
transmission-show debian.torrent
Name: debian-10.4.0-amd64-netinst.iso
File: debian.torrent
GENERAL
Name: debian-10.4.0-amd64-netinst.iso
Hash: a7fbe3ac2451fc6f29562ff034fe099c998d945e
Created by: Transmission/2.92 (14714)
Created on: Mon Jun 8 00:04:33 2020
Piece Count: 2688
Piece Size: 128.0 KiB
Total Size: 352.3 MB
Privacy: Public torrent
TRACKERS
FILES
debian-10.4.0-amd64-netinst.iso (352.3 MB)
Open the port which transmission running on your vps.
firewall-cmd --zone=public --add-port=51413/tcp --permanent
firewall-cmd --reload
Check it from your local pc.
sudo nmap $vps_ip -p51413
Host is up (0.24s latency).
PORT STATE SERVICE
51413/tcp open unknown
Nmap done: 1 IP address (1 host up) scanned in 1.74 seconds
Add the torrent and seed it with transmission's default username and password on your vps(with your own if you already change it):
transmission-remote -n "transmission:transmission" --add debian.torrent
localhost:9091/transmission/rpc/ responded: "success"
transmission-remote -n "transmission:transmission" --list
ID Done Have ETA Up Down Ratio Status Name
1 0% None Unknown 0.0 0.0 None Idle debian-10.4.0-amd64-netinst.iso
Sum: None 0.0 0.0
transmission-remote -n "transmission:transmission" -t 1 --start
localhost:9091/transmission/rpc/ responded: "success"
Get the debian.torrent from your vps into local pc.
scp root#$vps_ip:/root/debian.torrent /tmp
Now to try download it in your local pc.
aria2c --enable-dht=true /tmp/debian.torrent
06/08 09:28:04 [NOTICE] Downloading 1 item(s)
06/08 09:28:04 [NOTICE] IPv4 DHT: listening on UDP port 6921
06/08 09:28:04 [NOTICE] IPv4 BitTorrent: listening on TCP port 6956
06/08 09:28:04 [NOTICE] IPv6 BitTorrent: listening on TCP port 6956
*** Download Progress Summary as of Mon Jun 8 09:29:04 2020 ***
===============================================================================
[#a34431 0B/336MiB(0%) CN:0 SD:0 DL:0B]
FILE: /tmp/debian-10.4.0-amd64-netinst.iso
-------------------------------------------------------------------------------
I wait about one hour ,the download progress is always 0%.
If you're using DHT, you have to open a UDP port in your firewall and then, depending on what you're doing, you can specify that port to aria2c. From the docs:
DHT uses UDP. Since aria2 doesn't configure firewalls or routers for port forwarding, it's up to you to do it manually.
$ aria2c --enable-dht --dht-listen-port=6881 file.torrent
See this page for some more examples of using DHT with aria2c.
I am trying to access the dockerd daemon from a remote machine via tcp.
I will say first that I am aware of the security risk on non encrypted and will look to move but cant get this working.
I have setup things as best I can but cannot seem to connect from a remote machine.
I have the following in my daemon.json file
{
"hosts": ["tcp://172.16.16.62:2375", "unix:///var/run/docker.sock"]
}
I can see that it is listening on the correct port in netstat
tcp 0 0 hostname:2375 0.0.0.0:* LISTEN
I can even connect to it from the local host
docker -H tcp://172.16.16.62:2375 ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ddc2e3f97067 Image "/usr/sbin/sshd -D" 3 days ago Up 27 minutes 0.0.0.0:2200->22/tcp, 0.0.0.0:4400->8000/tcp epic_lamarr
7867cd6193df Image2 "/usr/sbin/sshd -D" 7 days ago Up 27 minutes 0.0.0.0:2201->22/tcp competent_brahmagupta
But from a remote host I get
docker -H tcp://172.16.16.62:2375 ps
Cannot connect to the Docker daemon at tcp://172.16.16.62:2375. Is the docker daemon running?
I can confirm that the traffic is getting there.
sudo tcpdump -ni any port 2375 -s 0
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on any, link-type LINUX_SLL (Linux cooked), capture size 262144 bytes
08:35:06.451656 IP 172.16.16.61.48096 > 172.16.16.62.2375: Flags [S], seq 3191742733, win 29200, options [mss 1460,sackOK,TS val 1080792310 ecr 0,nop,wscale 7], length 0
08:35:06.452992 IP 172.16.16.61.48098 > 172.16.16.62.2375: Flags [S], seq 4090360, win 29200, options [mss 1460,sackOK,TS val 1080792312 ecr 0,nop,wscale 7], length 0
I cannot seem to understand why this is not responding.
I'm using docker version of neo4j (v3.1.0) and I'm having difficulties connecting to neo4j server using neo4j-shell.
After running an instance of neo4r:3.1.0 docker, I run a bash inside the container:
$ docker exec -it neo4j /bin/bash
And from there I try to run the neo4j-shell like this:
/var/lib/neo4j/bin/neo4j-shell
But it errors:
$ /var/lib/neo4j/bin/neo4j-shell
ERROR (-v for expanded information):
Connection refused
-host Domain name or IP of host to connect to (default: localhost)
-port Port of host to connect to (default: 1337)
-name RMI name, i.e. rmi://<host>:<port>/<name> (default: shell)
-pid Process ID to connect to
-c Command line to execute. After executing it the shell exits
-file File containing commands to execute, or '-' to read from stdin. After executing it the shell exits
-readonly Connect in readonly mode (only for connecting with -path)
-path Points to a neo4j db path so that a local server can be started there
-config Points to a config file when starting a local server
Example arguments for remote:
-port 1337
-host 192.168.1.234 -port 1337 -name shell
-host localhost -readonly
...or no arguments for default values
Example arguments for local:
-path /path/to/db
-path /path/to/db -config /path/to/neo4j.config
-path /path/to/db -readonly
I also tried other hosts like: localhost, 127.0.0.1 and 172.17.0.6 (the container IP). Since it didn't work I tried to list open ports on my container:
$ netstat -l
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 :::7687 :::* LISTEN
tcp 0 0 :::7473 :::* LISTEN
tcp 0 0 :::7474 :::* LISTEN
Active UNIX domain sockets (only servers)
Proto RefCnt Flags Type State I-Node Path
As you can see there's no 1337 open! I've looked into the config file and the line for specifying port is commented out which means it should be set to its default value (1337).
Can anyone help me connect to neo4j using neo4j-shell?
BTW, the neo4j server is up and running and I can use its web access through port :7474.
In 3.1 it seems the shell is not enabled by default.
You will need to pass your own configuration file with the shell enabled :
Uncomment
# Enable a remote shell server which Neo4j Shell clients can log in to.
dbms.shell.enabled=true
(I find the amount of worker for changing one value in docker quite heavy but yeah..)
Or use the new cypher-shell :
ikwattro#graphaware-team ~> docker ps -a | grep 'neo4j'
34b3c6718504 neo4j:3.1.0 "/docker-entrypoint.s" 2 minutes ago Up 2 minutes 7473-7474/tcp, 7687/tcp compassionate_easley
2395bd0b1fe9 neo4j:3.1.0 "/docker-entrypoint.s" 5 minutes ago Exited (143) 3 minutes ago cranky_goldstine
949feacbc0f9 neo4j:3.1.0 "/docker-entrypoint.s" 5 minutes ago Exited (130) 5 minutes ago modest_boyd
c38572b078de neo4j:3.0.6-enterprise "/docker-entrypoint.s" 6 weeks ago Exited (0) 6 weeks ago fastfishpim_neo4j_1
ikwattro#graphaware-team ~> docker exec --interactive --tty compassionate_easley bin/cypher-shell
username: neo4j
password: *****
Connected to Neo4j 3.1.0 at bolt://localhost:7687 as user neo4j.
Type :help for a list of available commands or :exit to exit the shell.
Note that Cypher queries must end with a semicolon.
neo4j>
NB: Cypher-shell supports begin and commit :
neo4j> :begin
neo4j# create (n:Node);
Added 1 nodes, Added 1 labels
neo4j# :commit;
neo4j>
-
neo4j> :begin
neo4j# create (n:Person {name:"John"});
Added 1 nodes, Set 1 properties, Added 1 labels
neo4j# :rollback
neo4j> :commit
There is no open transaction to commit
neo4j>
http://neo4j.com/docs/operations-manual/current/tools/cypher-shell/
I am able to start two cassandra node instances up and running through docker.
docker run --name n1 -d tobert/cassandra -dc DC1 -rack RAC1
docker run --name n2 -d tobert/cassandra -seeds 172.17.0.2 -dc DC2 -rack RAC1
When I try to start the new node instance n3, then it doesn't through any error but I do no see any n3 instance came up, I am seeing only 2 nodes.
$ docker run --name n3 -d tobert/cassandra -seeds 172.17.0.2 -dc DC1 -rack RAC2
XXX
$ docker ps (doesnt show the third cassandra node)
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
8ab64fa86819 tobert/cassandra "/bin/cassandra-docke" 41 minutes ago Up 41 minutes 7000/tcp, 7199/tcp, 9042/tcp, 9160/tcp, 61621/tcp n2
125fc4ffba4d tobert/cassandra "/bin/cassandra-docke" 42 minutes ago Up 42 minutes 7000/tcp, 7199/tcp, 9042/tcp, 9160/tcp, 61621/tcp n1
$ docker exec -it n1 nodetool status
Datacenter: DC2
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns (effective) Host ID Rack
UN 172.17.0.3 82.43 KB 256 100.0% XXX RAC1
Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns (effective) Host ID Rack
UN 172.17.0.2 51.48 KB 256 100.0% XXX RAC1
Will anyone please let me know why is this happening. What conf need to be done to initiate more node instances. It is clear that the node instances more than 2 in my localhost is an issue here. Why?
Looks like sometimes we need to run the docker run command more than once in-order to start-up the new node. No idea why this happens.
I have assigned memory of 4GB to the docker container using command boot2docker --memory 4096 init which gave some space to add a new node which I was expecting to.
Finally here are the nodes that are up and running
$ docker exec -it n1 nodetool status
Datacenter: DC1
===============
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns (effective) Host ID Rack
UN 172.17.0.3 98.91 KB 256 64.5% 30156883-aafe-43b8-b8ee-fec2c9225778 RAC2
UN 172.17.0.2 51.51 KB 256 68.3% 486f457c-8be2-4844-9cd0-d5ef37b46cea RAC1
UN 172.17.0.4 98.97 KB 256 67.3% d19ad6a1-8138-4283-815c-3b223a33c987 RAC1
I m new to cassandra.I m trying to connect to cassandra bt couldnot connect.
the steps i m following are
1.start the server with command -
/root/Documents/apache-cassandra-0.6.6/bin/cassandra -f
2.on another terminal i m giving command
/root/Documents/apache-cassandra-0.6.6/bin/cassandra-cli
which is saying welcome to cassandra cli
3.then i m connecting too cassandra by giving the command
/root/Documents/apache-cassandra-0.6.6/bin/cassandra-cli
but i m getting exception as "Exception connecting to 10.10.10.142/9160 - java.net.NoRouteToHostException: No route to host
"
can anyone help me why i m getting such exception.
This has "nothing" to do with cassandra.
The documentation (regarding NoRouteToHostException) states that:
"Signals that an error occurred while attempting to connect a socket to a remote address and port. Typically, the remote host cannot be reached because of an intervening firewall, or if an intermediate router is down. "
Another option to consider is to add the port 7199 to the firewall or just to test it to see if you can access a 2 node system is to turn off the firewall in linux using " sudo service firewalld stop"
[dse#orion conf]$ dsetool status mars
DC: Cassandra Workload: Cassandra Graph: no
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Effective-Ownership VNodes Rack Health [0,1]
UN 10.0.0.165 250.03 KiB 100.00% 1 rack1 0.20
UN 10.0.0.20 656.65 KiB 100.00% 256 rack1 0.40