OS X Firewall Block all incoming Connections Affecting Software Updates?

I just bought a 2017 Macbook Pro with the latest OS (Mojave). In the OS X Mojave Security and Privacy-Firewall settings, I set Firewall to “Block all incoming connections” as I am extra cautious, but will my software (such as Chrome web browser, Firefox, etc.) still get new updates? For example, will my Firefox browser still get the latest software updates or will I have to manually check for software updates because the firewall is blocking all incoming connections?

Connections begin slowly on ubuntu 18.04 ethernet

Recently installed ubuntu 18.04 on a system that dual boots with windows 10. I noticed that it takes much longer to establish any connections over the internet, taking multiple seconds to load any webpage or to connect to any of the package manager servers or etc. Interestingly, streaming speed hasn’t changed at all. I still have very fast download speed, it’s just the initial connection that takes a very extended period of time. Any suggestions as to where to look to fix this?

How to see remote SSH connections on my server?

I’m currently using VSCode’s Remote SSH extension to connect to a remote server and edit source code locally.

I was just curious, is there a way to see what connections are established on my remote server? For example, I’m using an SSH client called Xshell to connect to the server. Using Xshell, would there be a command I could run to output what connections are currently established?

Calculating all flight connections

I am working on an API to return all the possible flight route between point A and B.

I have a set of data which includes the flight number ,Airline , from airport , to airport , departure time, arrival time.

Keep in mind i am also catering connecting flights. But the connections can only happen between hubs.

I have 5 Hubs and 5 Airlines. Each hub is the base for the airline i.e Dubai for Emirates, Istanbul for Turkish Need the API to calculate all possible routes based on all the flights of these 5 airlines.

The sample result could be : (Assuming Istanbul , London & Nairobi are hubs)

User wants to go from Dubai to New York

  • Route 1: Dubai to New York (EK203)
  • Route 2: Connecting Dubai to Istanbul to New York (EK123 , TK3)
  • Route 3: Dubai to Istanbul to London to Nairobi to New York

Currently this system is build on SQL DB and .NET API. We are able to do all above but it works fine for direct flights but it takes up to 30 seconds when the connections are more than 2.

The Data set we are running this on includes all the flights for all 5 airlines so the data set is huge.

I was suggested to use GraphQL.

I am looking for suggestions on how to bring this to under 2 seconds of response.

Below is a chunk of SQL Query:

WITH RoutesCTE AS (  select  ( dgl_city . Title + ', ' + dgl_country . Title + '|' + agl_city . Title + ', ' + agl_country . Title ) as [Route]  , 0 as TransfersCount    , CAST (( '[{' +    '"RosterID":"' + CAST ( ISNULL ( rtt . RosterID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"FlightNumber":"' + CAST ( ISNULL ( rtt . FlightNumber , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ReoccuranceCode":"' + ISNULL ( rtt . Code , '' ) + '",' +  '"TravelerAspNetUserID":"' + CAST ( ISNULL ( rtt . TravelerAspNetUserID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"TravelerUserCode":"' + ISNULL ( t_asp . Code , '' ) + '",' +    '"SortOrder":"' + Cast (( 0 ) AS NVARCHAR ( MAX )) + '",' +    '"DepartureAirportIATA":"' + ISNULL ( rtt . DepartureAirportIATA , '' ) + '",' +  '"DepartureAirportTitle":"' + ISNULL ( da . Title , '' ) + '",' +    '"DepartureGeoLocationCityID":"' + CAST ( ISNULL ( dgl_city . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityTitle":"' + CAST ( ISNULL ( dgl_city . Title , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsHub":"' + CAST ( ISNULL ( dgl_city . IsHub , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsExceptionEnabledAtPickup":"' + CAST ( ISNULL ( dgl_city . IsExceptionEnabledAtPickup , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsExceptionEnabledAtDropoff":"' + CAST ( ISNULL ( dgl_city . IsExceptionEnabledAtDropoff , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityISOCode":"' + CAST ( ISNULL ( dgl_city . ISOCode , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryID":"' + CAST ( ISNULL ( dgl_country . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryTitle":"' + CAST ( ISNULL ( dgl_country . Title , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryISOCode":"' + CAST ( ISNULL ( dgl_country . ISOCode , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureDateTime":"' + CAST ( ISNULL ( rtt . DepartureDateTime , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureAirportTerminal":"' + CAST ( ISNULL ( rtt . DepartureTerminal , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureAirportGate":"' + ISNULL ( rtt . DepartureGate , '' ) + '",' +    '"ArrivalAirportIATA":"' + ISNULL ( rtt . ArrivalAirportIATA , '' ) + '",' +  '"ArrivalAirportTitle":"' + ISNULL ( aa . Title , '' ) + '",' +    '"ArrivalGeoLocationCityID":"' + CAST ( ISNULL ( agl_city . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityTitle":"' + ISNULL ( agl_city . Title , '' ) + '",' +  '"ArrivalGeoLocationCityIsHub":"' + CAST ( ISNULL ( agl_city . IsHub , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityIsExceptionEnabledAtPickup":"' + CAST ( ISNULL ( agl_city . IsExceptionEnabledAtPickup , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityIsExceptionEnabledAtDropoff":"' + CAST ( ISNULL ( agl_city . IsExceptionEnabledAtDropoff , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityISOCode":"' + CAST ( ISNULL ( agl_city . ISOCOde , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCountryID":"' + CAST ( ISNULL ( agl_country . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCountryTitle":"' + ISNULL ( agl_country . Title , '' ) + '",' +  '"ArrivalGeoLocationCountryISOCode":"' + ISNULL ( agl_country . ISOCode , '' ) + '",' +  '"ArrivalDateTime":"' + CAST ( ISNULL ( rtt . ArrivalDateTime , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalAirportTerminal":"' + ISNULL ( rtt . ArrivalTerminal , '' ) + '",' +  '"ArrivalAirportGate":"' + ISNULL ( rtt . ArrivalGate , '' ) + '",' +    '"AirlineIATA":"' + ISNULL ( rtt . AirlineIATA , '' ) + '",' +  '"AirlineTitle":"' + ISNULL ( air . Title , '' ) + '"' +    '}' + ( case  when agl_city . GeoLocationID = @ArrivalGeoLocationID then ']'  WHEN rtt . ArrivalAirportIATA IN ( SELECT a . IATA FROM @ArrivalAirportExceptions a ) THEN ']'  else ''  end )  ) AS NVARCHAR ( MAX )) as JsonObj ,    rtt . DepartureAirportIATA ,  rtt . ArrivalAirportIATA ,  rtt . DepartureDateTime ,  rtt . ArrivalDateTime ,    da . OriginGeoLocationID as DepartureGeoLocationID ,  dgl_city . Title as DepartureCityTitle ,  dgl_city . UTCOffset as DepartureCityUTCOffset ,  dgl_city . IsHub as DepartureCityIsHub ,  dgl_city . ISOCode as DepartureCityISOCode ,  dgl_city . IsExceptionEnabledAtPickup as DepartureCityIsExceptionEnabledAtPickup ,  dgl_city . IsExceptionEnabledAtDropoff as DepartureCityIsExceptionEnabledAtDropoff ,  dgl_city . IsDSTEnabled as DepartureCityIsDSTEnabled ,  dgl_country . Title as DepartureCountryTitle ,  dgl_country . ISOCOde as DepartureCountryISOCode ,  dgl_country . VAT as DepartureCountryVATInPercentage ,  dgl_country . NFSTaxRegisteration as DepartureCountryNFSTaxRegisteration ,  aa . OriginGeoLocationID as ArrivalGeoLocationID ,  agl_city . Title as ArrivalCityTitle ,  agl_city . IsHub as ArrivalCityIsHub ,  agl_city . ISOCode as ArrivalCityISOCOde ,  agl_city . IsExceptionEnabledAtPickup as ArrivalCityIsExceptionEnabledAtPickup ,  agl_city . IsExceptionEnabledAtDropoff as ArrivalCityIsExceptionEnabledAtDropoff ,  agl_city . IsDSTEnabled as ArrivalCityIsDSTEnabled ,  agl_city . UTCOffset as ArrivalCityUTCOffset ,  agl_country . Title as ArrivalCountryTitle ,  agl_country . ISOCode as ArrivalCountryISOCode ,  agl_country . VAT as ArrivalCountryVATInPercentage ,  agl_country . NFSTaxRegisteration as ArrivalCountryNFSTaxRegisteration ,  rtt . TravelerAspNetUserID  , rtt . AirlineIATA    FROM @RosterTempTable rtt    INNER JOIN dbo . Airlines air  ON rtt . AirlineIATA = air . IATA    INNER JOIN dbo . Airports da  ON rtt . DepartureAirportIATA = da . IATA  INNER JOIN dbo . GeoLocations dgl_city  ON da . OriginGeoLocationID = dgl_city . GeoLocationID  INNER JOIN dbo . GeoLocations dgl_country  ON dgl_city . GeoLocationCountryID = dgl_country . GeoLocationID    INNER JOIN dbo . Airports aa  ON rtt . ArrivalAirportIATA = aa . IATA  INNER JOIN dbo . GeoLocations agl_city  ON aa . OriginGeoLocationID = agl_city . GeoLocationID  INNER JOIN dbo . GeoLocations agl_country  ON agl_city . GeoLocationCountryID = agl_country . GeoLocationID    INNER JOIN dbo . AspNetUsers t_asp  ON rtt . TravelerAspNetUserID = t_asp . Id    INNER JOIN dbo . Tiers tier  ON t_asp . TierID = tier . TierID  AND ( t_asp . KycApproval IS NOT NULL AND t_asp . KycApproval = 'true' )  AND tier . IsBarded = 'false'    UNION ALL    SELECT    r . [Route] + '|' + ( r1_agl_city . Title + ', ' + r1_agl_country . Title )  , TransfersCount + 1  , r . JsonObj + CAST (( ',{' +    '"RosterID":"' + CAST ( ISNULL ( r1 . RosterID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"FlightNumber":"' + CAST ( ISNULL ( r1 . FlightNumber , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ReoccuranceCode":"' + ISNULL ( r1 . Code , '' ) + '",' +  '"TravelerAspNetUserID":"' + CAST ( ISNULL ( r1 . TravelerAspNetUserID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"TravelerUserCode":"' + ISNULL ( t_asp . Code , '' ) + '",' +    '"DepartureAirportIATA":"' + ISNULL ( r1 . DepartureAirportIATA , '' ) + '",' +  '"DepartureAirportTitle":"' + ISNULL ( r1_da . Title , '' ) + '",' +    '"SortOrder":"' + Cast (( TransfersCount + 1 ) AS NVARCHAR ( MAX )) + '",' +    '"DepartureGeoLocationCityID":"' + CAST ( ISNULL ( r1_dgl_city . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityTitle":"' + CAST ( ISNULL ( r1_dgl_city . Title , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsHub":"' + CAST ( ISNULL ( r1_dgl_city . IsHub , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsExceptionEnabledAtPickup":"' + CAST ( ISNULL ( r1_dgl_city . IsExceptionEnabledAtPickup , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityIsExceptionEnabledAtDropoff":"' + CAST ( ISNULL ( r1_dgl_city . IsExceptionEnabledAtDropoff , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCityISOCode":"' + CAST ( ISNULL ( r1_dgl_city . ISOCode , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryID":"' + CAST ( ISNULL ( r1_dgl_country . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryTitle":"' + CAST ( ISNULL ( r1_dgl_country . Title , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureGeoLocationCountryISOCode":"' + CAST ( ISNULL ( r1_dgl_country . ISOCode , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureDateTime":"' + CAST ( ISNULL ( r1 . DepartureDateTime , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureAirportTerminal":"' + CAST ( ISNULL ( r1 . DepartureTerminal , '' ) AS NVARCHAR ( MAX )) + '",' +  '"DepartureAirportGate":"' + ISNULL ( r1 . DepartureGate , '' ) + '",' +    '"ArrivalAirportIATA":"' + ISNULL ( r1 . ArrivalAirportIATA , '' ) + '",' +  '"ArrivalAirportTitle":"' + ISNULL ( r1_aa . Title , '' ) + '",' +    '"ArrivalCityID":"' + CAST ( ISNULL ( r1_agl_city . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityTitle":"' + ISNULL ( r1_agl_city . Title , '' ) + '",' +  '"ArrivalGeoLocationCityIsHub":"' + CAST ( ISNULL ( r1_agl_city . IsHub , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityIsExceptionEnabledAtPickup":"' + CAST ( ISNULL ( r1_agl_city . IsExceptionEnabledAtPickup , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityIsExceptionEnabledAtDropoff":"' + CAST ( ISNULL ( r1_agl_city . IsExceptionEnabledAtDropoff , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCityISOCode":"' + CAST ( ISNULL ( r1_agl_city . ISOCode , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCountryID":"' + CAST ( ISNULL ( r1_agl_country . GeoLocationID , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalGeoLocationCountryTitle":"' + ISNULL ( r1_agl_country . Title , '' ) + '",' +  '"ArrivalGeoLocationCountryISOCode":"' + ISNULL ( r1_agl_country . ISOCode , '' ) + '",' +  '"ArrivalDateTime":"' + CAST ( ISNULL ( r1 . ArrivalDateTime , '' ) AS NVARCHAR ( MAX )) + '",' +  '"ArrivalAirportTerminal":"' + ISNULL ( r1 . ArrivalTerminal , '' ) + '",' +  '"ArrivalAirportGate":"' + ISNULL ( r1 . ArrivalGate , '' ) + '",' +    '"AirlineIATA":"' + ISNULL ( r1 . AirlineIATA , '' ) + '",' +  '"AirlineTitle":"' + ISNULL ( air . Title , '' ) + '"' +    '}' + ( case  when r1_agl_city . GeoLocationID = @ArrivalGeoLocationID then ']'  WHEN r1 . ArrivalAirportIATA IN ( SELECT a . IATA FROM @ArrivalAirportExceptions a ) THEN ']'  else ''  end )  ) AS NVARCHAR ( MAX )),    r . DepartureAirportIATA ,  r1 . ArrivalAirportIATA ,  r . DepartureDateTime ,  r1 . ArrivalDateTime ,    r . DepartureGeoLocationID ,  r . DepartureCityTitle ,  r . DepartureCityUTCOffset ,  r . DepartureCityIsHub ,  r . DepartureCityISOCode ,  r . DepartureCityIsExceptionEnabledAtPickup ,  r . DepartureCityIsExceptionEnabledAtDropoff ,  r . DepartureCityIsDSTEnabled ,  r . DepartureCountryTitle ,  r . DepartureCountryISOCode ,  r . DepartureCountryVATInPercentage ,  r . DepartureCountryNFSTaxRegisteration ,  r1_aa . OriginGeoLocationID as ArrivalGeoLocationID ,  r1_agl_city . Title as ArrivalCityTitle ,  r1_agl_City . IsHub AS ArrivalCityIsHub ,  r1_agl_City . ISOCode AS ArrivalCityISOCode ,  r1_agl_City . IsExceptionEnabledAtPickup AS ArrivalCityIsExceptionEnabledAtPickup ,  r1_agl_City . IsExceptionEnabledAtDropoff AS ArrivalCityIsExceptionEnabledAtDropoff ,  r1_agl_City . IsDSTEnabled AS ArrivalCityIsDSTEnabled ,  r1_agl_City . UTCOffset AS ArrivalCityUTCOffset ,  r1_agl_country . Title as ArrivalCountryTitle ,  r1_agl_country . ISOCode as ArrivalCountryISOCode ,  r1_agl_country . VAT as ArrivalCountryVATInPercentage ,  r1_agl_country . NFSTaxRegisteration as ArrivalCountryNFSTaxRegisteration ,  r1 . TravelerAspNetUserID ,  r1 . AirlineIATA    FROM RoutesCTE r    JOIN @RosterTempTable r1    INNER JOIN dbo . Airlines air  ON r1 . AirlineIATA = air . IATA    INNER JOIN dbo . Airports r1_da  ON r1 . DepartureAirportIATA = r1_da . IATA  INNER JOIN dbo . GeoLocations r1_dgl_city  ON r1_da . OriginGeoLocationID = r1_dgl_city . GeoLocationID  INNER JOIN dbo . GeoLocations r1_dgl_country  ON r1_dgl_city . GeoLocationCountryID = r1_dgl_country . GeoLocationID    INNER JOIN dbo . Airports r1_aa  ON r1 . ArrivalAirportIATA = r1_aa . IATA  INNER JOIN dbo . GeoLocations r1_agl_city  ON r1_aa . OriginGeoLocationID = r1_agl_city . GeoLocationID  INNER JOIN dbo . GeoLocations r1_agl_country  ON r1_agl_city . GeoLocationCountryID = r1_agl_country . GeoLocationID    INNER JOIN dbo . AspNetUsers t_asp  ON r1 . TravelerAspNetUserID = t_asp . Id    INNER JOIN dbo . Tiers tier  ON t_asp . TierID = tier . TierID    --ON (r.ArrivalAirportIATA = r1.DepartureAirportIATA OR (r.ArrivalCityTitle + ', ' + r.ArrivalCountryTitle) = (r1_dgl_city.Title + ', ' + r1_dgl_country.Title))  --ON (((r.AirlineIATA IN ('ey', 'ek') AND r1.AirlineIATA IN ('ey', 'ek')) AND ((r.ArrivalAirportIATA <> r1.DepartureAirportIATA) OR (r.ArrivalAirportIATA <> r1.DepartureAirportIATA))) OR (r.ArrivalAirportIATA = r1.DepartureAirportIATA))  ON (( r . ArrivalAirportIATA <> r1 . DepartureAirportIATA ) OR ( r . ArrivalAirportIATA = r1 . DepartureAirportIATA ))    AND r1 . ArrivalAirportIATA <> r . DepartureAirportIATA  AND (( DATEDIFF ( HOUR , r . ArrivalDateTime , r1 . DepartureDateTime ) > 0 ) AND ( DATEDIFF ( HOUR , r . ArrivalDateTime , r1 . DepartureDateTime ) >= ( @PickupCuttoffTimeInHours + @DeliveryCuttoffTimeInHours + @HandlerCuttoffTimeInHours )) AND ( DATEDIFF ( DAY , r . ArrivalDateTime , r1 . DepartureDateTime ) <= 5 ))    AND PATINDEX ( '%' + ( r1_agl_city . Title + ', ' + r1_agl_country . Title ) + '%' , r . [Route] ) = 0    AND ( r . ArrivalCityIsHub = 'true' OR r . TravelerAspNetUserID = r1 . TravelerAspNetUserID )  AND t_asp . KycApproval = 'true'  AND tier . IsBarded = 'false'  )  SELECT  TOP 500  [Route] ,    TransfersCount AS TotalNumberOfConnectingFlights    , JsonObj , DepartureDateTime , ArrivalDateTime , DATEDIFF ( MILLISECOND , DepartureDateTime , ArrivalDateTime ) as CalculatedTime ,  DepartureGeoLocationID ,  DepartureCityTitle ,  DepartureCityUTCOffset ,  DepartureCityIsHub ,  DepartureCityIsExceptionEnabledAtPickup ,  DepartureCityIsExceptionEnabledAtDropoff ,  DepartureCityIsDSTEnabled ,  DepartureCountryVATInPercentage ,  DepartureCountryNFSTaxRegisteration ,  DepartureCityISOCode ,  DepartureCountryTitle ,  DepartureCountryISOCode ,  ArrivalGeoLocationID ,  ArrivalCityTitle ,  ArrivalCityUTCOffset ,  ArrivalCityIsHub ,  ArrivalCityIsExceptionEnabledAtPickup ,  ArrivalCityIsExceptionEnabledAtDropoff ,  ArrivalCityISOCode ,  ArrivalCountryTitle ,  ArrivalCountryISOCode ,  ArrivalCityIsDSTEnabled ,  ArrivalCountryVATInPercentage ,  ArrivalCountryNFSTaxRegisteration    FROM RoutesCTE  WHERE TransfersCount <= 4  AND ( DepartureGeoLocationID = @DepartureGeoLocationID AND ArrivalGeoLocationID = @ArrivalGeoLocationID )  ORDER BY DepartureDateTime ASC , DATEDIFF ( MILLISECOND , DepartureDateTime , ArrivalDateTime ) ASC 

Apache hangs after every 2-3 weeks, with closed_wait connections increasing until it is restarted

We have a cluster setup of 3 server, on all 3 servers weblogic is running to host website. On the top of weblogic using Apache as load balancer.

Last year I had upgraded Apache http server from 2.4.9 to 2.4.29. Before upgrade things were working fine but post upgrade after every 2-4 weeks Apache hangs. Website becomes inaccessible, on checking the server we don’t see any error in fact the moment when apache hangs it stops logging too.

We monitored and found no abnormal memory usage, no suspicious type of request to website, no suspicious process running before the issue occurs.

After exploring over the internet, I found that problem could be related to MPM configuration. Apache was using event MPM but I found that event MPM configuration was not declared in apache configuration, I think during upgrade default configuration was replaced by old configuration.

So we have modified MPM configuration to use below event mpm configuration and this change worked. We did not face this issue for next 6 months.

StartServers 4 MinSpareThreads 256 MaxSpareThreads 512 ThreadsPerChild 64 MaxRequestWorkers 2048 MaxConnectionsPerChild 0

We thought it is fixed but now after 6 months Apache hangs again, only symptoms we can see increasing closed_wait connections from 20 to 550 in next 1 hours, no accessibility of website, apache stopped logging to it’s ssl and error logs, we don’t see any abnormal behaviour in different running process data, memory usage, also don’t see any suspicious request before issue occurred.

Shouldn’t NASA JPL’s network be secure against Raspberry Pi connections authorized or not?

The question What information was stolen from JPL during the Raspberry Pi hack? refers to an event in recent news (e.g. Engadget’s A rogue Raspberry Pi helped hackers access NASA JPL systems) and references NASA’s Office of Inspector General June 2019 report Cybersecurity Management and Oversight a the Jet Propulsion Laboratory which states on page 17 in the section titled Incomplete and Inaccurate System Component Inventory:

Moreover, system administrators did not consistently update the inventory system when they added devices to the network. Specifically, we found that 8 of 11 system administrators responsible for managing the 13 systems in our sample maintain a separate inventory spreadsheet of their systems from which they periodically update the information manually in the ITSDB. One system administrator told us he does not regularly enter new devices into the ITSDB as required because the database’s updating function sometimes does not work and he later forgets to enter the asset information. Consequently, assets can be added to the network without being properly identified and vetted by security officials. The April 2018 cyberattack exploited this particular weakness when the hacker accessed the JPL network by targeting a Raspberry Pi computer that was not authorized to be attached to the JPL network. 32 The device should not have been permitted on the JPL network without the JPL OCIO’s review and approval.

To me it sounds like overall the report laments the failure to keep an updated list of devices that are authorized to be connected the network as the major security issue; if they’d only had better record-keeping, this wouldn’t have happened. But it seems to me that no matter how well you document after the fact what’s supposed to be connected that doesn’t in any way prevent inadvertent, accidental, or purposeful connection of an unauthorized device, for example “just for a minute” to download a Raspberry Pi update of some kind.

Question: Shouldn’t such a valuable US government network be secure against all connections equally, authorized or not?

This answer starts to outline the seriousness of the breach.

Ubuntu 18.04 will not connect to Android Hot Spot, knocks out other land based connections

Tower computer, Quad core, Ubuntu fresh full install of version 18.04. Wifi antenna USB 2.4GHz & 5.0GHz high gain. (No laptop involved). Android phone set up as a Wifi Hot Spot with Data connection ‘On’.

Issue: Antenna picks up wifi signal transmitted by phone set for hot spot just fine. But Ubuntu will not connect to the internet. ‘Connection Failed. Activation of network connection failed’.

My other machine with Win7 connects to the phone and internet fine.

Once I try to connect to the phone and get the error message above, that knocks out the previously working wifi connection to my main land based wifi signal. Still see the AP it just will no longer connect. I have to reboot the machine to restore usage of my primary land based wifi connection.

Something in 18.04 is blocking connection to the internet through the phone. When this equipment setup was Ubuntu 16.04 it did fine connecting to the phone and internet many times over many months and many different locations (I travel extensively). So it’s not an equipment issue.

I followed the advice in this thread but nothing there helped, plus it doesn’t mention that just trying to use as a hot spot causes a working connection to fail and require a reboot: USB Tethering not working…

Any fresh ideas? 18.04 is over a year old, someone much have solved this issue by now. Right?

Thanks for any help as I use my phone tethered all the time and need it to work reliably.