Is There An Established Way To Send Code Over a Network?

Let’s say I have two computers on a network. I want to write code in some language on machine A, send the code in an efficient way over a network, and run the code on machine B. It seems to me that this would be inherently slow and would run into a bundle of problems (not having required dependencies) but perhaps some work has already been done on this problem? Is there any known processes or systems that already do this?

Direct peer connection cannot be established in Zerotier

I have two boxes with ip addresses and Both are directly accessible to each other and ports 9993 are telnetable. However, neither could see the other in the list of zerotier-cli listpeers.

I also tried adding hints to local.conf as this

    {             "virtual": {                     "e4465b2ccc": {                             "role": "UPSTREAM",                             "try": [ "" ]                     }             }     } 

which doesn’t help. All firewalls are turned off and selinux is disabled. One box is Archlinux while the other Centos 7. Zerotier version is 1.2.12.

What’s going wrong here?

$Whether\ the\ CTL\ formula\ M^{‘},\ s_0 \models EG\ AF\ p\ is\ established\ or\ not\ in\ this\ model\ M?$

I have been learning Verification by model checking recently and I get the following question:

$ Whether\ the\ CTL\ formula\ M^{‘},\ s_{0} \models EG\ AF\ p\ is\ established\ or\ not\ in\ this\ model\ M\ ?$

And there is the description of model M.Model

I think it is incorrect because there is a deadlock or infinite loop about $ s_0$ after the state is starting from $ s_0$ , which make it invalid under $ EG\ AF\ $ condition.

if not mind, could anyone tell me my thought is right or wrong? And prove it right or give a counterexample.

Thanks in advances.

Established Advertising Business For London/Essex

I am offering for sale my very established leaflet distribution service which specializes in leaflet deliveries for the East London and Essex region within the UK. The URL's are and also the is included.

Due to the nature of the target audience (London/Essex) the new owner should most certainly be UK based (could not realistically be operated in other countries). Better still if the new owner was London based however the service could continue to be managed…

Established Advertising Business For London/Essex

Postgresql Database connection could not be established

I had an error with PostgreSQL.

Here is the entire error I get:

Database connection could not be established with this configuration, try again. could not connect to server: Connection refused     Is the server running on host "localhost" ( and accepting     TCP/IP connections on port 5432? could not connect to server: Address not available     Is the server running on host "localhost" (::1) and accepting     TCP/IP connections on port 5432? 

I add the user and database I create on PostgreSQL on a setup wizard using docker.

Please help me to find out what’s wrong.

Thank You!

The role of the root switch after Spanning Tree Protocol has established a tree network in a LAN?

In Spanning Tree Protocol, a root switch is selected at first, and then somehow, the shortest path from each other switch to the root is obtained. Thus we established a tree network.

My questions are:

  • After the tree network is established, does the root switch act as a center in the network? In other words, all the traffic originated from other switch would first flow into the root switch along the shortest path and then routed to its destination by the root switch, also along the shortest path.
  • If it’s not the case, why does the protocol calculate a tree such that the path between each non-root switches and the root is minimized? As far as I can see, a minimum spanning tree would work better, which is not difficult to calculate.