Internet connection issue after sleep

When I leave my computer alone and it enters sleep mode, after I return it cannot connect to the WiFi unlike before. I don’t alter anything, I just leave it be but upon returning it simply cannot connect to any WiFi connection.

I’m using Ubuntu 18.04 and it’s on a Dual Boot with Windows 10, if that changes anything.

What can I do to fix this issue? Thanks

How to setup squid-deb-proxy and squid-deb-proxy-client to be more autonomous (to work without internet)?

I have server with installed squid-deb-proxy. Let’s say that its IP is 10.13.3.7.
I have installed squid-deb-proxy-client on other machines (let’s name them clients). Server and clients are in the same network and run Ubuntu 16.04.6 LTS.

Yesterday night I have downloaded all updates from one of the clients. So I expect that Squid Deb cache is filled with headers and packages.

On today morning there is no internet because of WAN (ISP) maintenance. I can’t ping anything outside the LAN. I can ping 10.13.3.7 from clients.

Thus when I run sudo apt update on clients I see the following messages:

0% [Working]
0% [Waiting for headers]
Err:N http://archive.ubuntu.com/ubuntu release InRelease
Connection failed [IP: 10.13.3.7 8000]

W: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/release/InRelease Connection failed [IP: 10.13.3.7 8000]
… W: Some index files failed to download. They have been ignored, or old ones used instead.

and same for sudo apt upgrade or sudo apt install ...:

0% [Waiting for headers]
Err:N http://archive.ubuntu.com/ubuntu xenial/pocket arch name arch version
Connection failed [IP: 10.13.3.7 8000]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/….deb Connection failed [IP: 10.13.3.7 8000]
E: Unable to fetch some archives, maybe run apt-get update or try with –fix-missing?

Is it possible to work without internet and get packages from local squid-deb-proxy cache?

two separate networks served over one internet connection with second network using VPN

We need two distinct device(computer,phone) sets (A vague “set” term used as we are open to different suggested solutions separate networks, VLANs, etc.)

  1. the first set should have regular internet access
  2. the second set should have internet access only as provided by a filter company using their VPN (and NOT regular internet access as available to the first set.)

We have

  • one internet connection using a modem router (TP-Link Archer VR300)
  • old TP-LinkTL-WR740N
    • router spec https://www.tp-link.com/en/products/details/TL-WR740N.html
    • dd-wrt firmware installed so it supports a WAN connection type of PPTP,L2TP for connecting to the VPN
  • TP-Link Archer VR400 also could be available

A partial solution suggested elsewhere was for the second router to be connected using its WAN port into the LAN port of the modem router. And the second router to use a WAN connection type supported by the VPN server, such as PPTP. When applying this, then devices connected to the second router for a time did have filtered internet from the VPN. Connecting one of the computer devices directly to the VPN using software provided by the filter company of the VPN does work, however there is no DNS and/or internet when connected by way of the VPN in the router. It is difficult to track down the issue when using the router if a configuration error by us or a problem with the VPN server, there was a time in which we had a WAN IP assigned of 100.80.0.14 however we never get one any more…)

Internet routers, network drops from one

I have two routers home and from one the network keeps dropping, even we bought a new router the network keeps droping and from the main router the network doesnt drop, its just the secondary, it drops for a second then its up then drops again the back again for 20 seconds at most than its fine for like half an hour atleast it was like that last night, most of the time it drops at random times. Any help on how I can fix this problem? Thank you in advance!

AWS VPC: Internet Gateway vs NAT

This and this are quite related to my question. Although it seems to have answered quite a lot of people’s doubts, I am still struggling to understand if this setup is specific to AWS or in general networking. If its the latter, then I need to revisit my basics. I suspect that already and hence the question.

My understanding

If a private network is connected to the Internet, then its hosts need to have public IPs to be uniquely identifiable on the Internet. All the traffic to the internet, inbound or outbound, happens with this Public IP address. A host from this network when connected to the Internet gets a Public IP. A packet originating from this host to say www.google.com will have the host’s private address in the packet which will ultimately get replaced by its public IP address by the NAT device (which is installed on the router/the default Gateway) which is as illustrated here. This is how most of the Internet (except IPV6) runs.

Now, in AWS

  • when you create a Public Subnet and enable auto-assign Public IPs, you are essentially informing the Internet Gateway to switch the private address of the EC2 instance with the public IP address of the EC2 instance in the request packets originating from this EC2 instance while routing its requests out on the internet and vice-versa on the way in. Is my understanding right?
  • when you create a Private Subnet (by not attaching it to the Internet Gateway), you are keeping it private. Then, we consciously make sure that we keep the auto-assign Public IP disabled. When we launch EC2 instances inside this private subnet, we, do not, therefore, get to see, the public IPs on the EC2 console. This also means that instances in this subnet are not visible to the internet. Now, if I connect this private subnet to a NAT device (which, of course, is on the public subnet) (please do not confuse me with what a NAT Gateway does better, at this moment), then, I am essentially, leaving the NAT device to figure out public IP to assign for a specific host X from the private subnet which has requested to communicate with the internet as a public IP is needed to communicate with the Internet.

    Now,

    • Is this not something that a Router/(Internet) Gateway already and also does in AWS and in general networking? Isn’t the assignment of public IPs to hosts on a network and keeping replacing the private IP address with the public IP address in the packets (that originate from a host on this network) on their way out to the Internet is something that is carried out by a router?
    • Say the NAT device figures out the IP 1.2.3.4 to be assigned to this host of the private subnet. If, “somehow”, this IP becomes known on the Internet, then this host on the private subnet should become reachable from the Internet, too, unless the NAT device pulls some trick (see follow up question). Is my understanding right? Now, AWS says that the NAT device does not allow inbound communication. Is that like a counter to the fact that even if the public IP 1.2.3.4 (that the NAT device assigns to the host of this private subnet) becomes known, the inbound connections are force restricted?
    • Also, AWS allows you to enable auto-assign Public IPs on a private subnet, too. And I can confirm that I can see EC2 instances on private subnet with a Public IP. So, now you have a Private Subnet (as they are not connected to the Internet Gateway in the routing tables) with instances having a Public IP (as you enabled the auto-assign Public IPs on a private subnet). How is that supposed to be interpreted?

Protecting Android debug bridge that is connected to the internet

I have an android device which acts as a brain for my home security that has access to cameras, heat sensors, motion sensors and some appliances.

I have enabled android debug bridge on my android device so I can send commands if I am away from home, like querying my motion sensors.

How can I add a level of security for my android device which is left exposed to the internet?

Ubuntu 18.04 Can’t connect to internet via ethernet after update

I have Ubuntu 18.04 installed since almost a year and never had problems with it.
Yesterday I updated my system and after a reboot i couldn’t connect to internet via ethernet.
When i check my IP address it says something starting with 10.xxx.xxx.xx Normally my IP address is 192.168.178.52.
If i type the IP address of my router into my browser it can’t connect to it either.
Over here on Windows everything works fine.

restrict remote desktop users access server from internet [migrated]

I have approx 10 remote desktop users who are accessing a server from a remote desktop connection. 5 users are connecting to the server within the local environment and the remaining 5 are accessing from the internet.

I want to restrict the local 5 users from connecting to the server from the internet. Please guide.

Server OS: Windows Server 2012 Standard

App that has no internet acces still loads ads

I’ve downloaded an app in the playstore, and since I don’t need to acces the internet, I disabled acces to both mobile data and wifi. What I see is that it does not consume any data (0 bytes according to settings), but if I open the app it still has ad banners. Now I am curious, does this mean that either it has preloaded ads, or is this something that comes from the play store?

PS: I can also tap the ads so that the play store gets opened and loads the ad’s app page, which gave me the idea that the ads are managed by the app store, not by the app itself. Also, it is a chess app. If I give it acces to the internet it’ll automatically share my statistics, which is why I really want to make sure that it has no network acces.