I'm using a Cisco client to connect to a VPN but also using Synergy (Symless) to connect to the machine. It works fine initially but will drop out after machine sleep (or sometimes seemingly randomly), then I have to restart the VPN connection. Not the end of the world, but it is irritating.
Are there any config changes I can do to Networks settings, VPN or Synergy to stop this dropping out?
Found this which I hope will fix it.
https://blog.lan-tech.ca/2013/02/21/access-local-and-vpn-network-simultaneously/
"you just need to add the local devices to the windows routing tables so that it knows to access them when the VPN is active.
See the windows “route” command – E.G. route -p add MASK 255.0.0.0 METRIC IF
To help discover what you need to use, disconnect from your VPN, make sure you can connect to your local device, then run a “route print” show the current active routes and find your device. (generally in the IPv4 Route Table)
It will also list the ‘Metric’ to use, and at the top of the listing is the “Interface List” which lists the network interfaces on your system. You’ll need to figure out which one to use. For example, I know my system has a gigabit network adapter and in the list I see a “Intel(R) Gigabit Network Connection” – bingo – that’s it. The first column is the interface id, 49 in my case.
The “-p” option makes your configuration persistent – meaning that it will be there again next time you boot.
SO, as an example, let’s say I want a local network share at 192.168.1.43 to be accessible to my machine while connected to the VPN, so I would add the route like so:
route -p add 192.168.1.43 MASK 255.0.0.0 192.168.1.1 METRIC 15 IF 49
Now if I run route print, I see this new route in the list of persistent routes for IPv4.
I turn my VPN back on, and instead of the device ‘disappearing’ as it normally does, windows can still find it because it is in the persistent route list."
Related
Followed this tutorial to setup two ec2 instances: 12 . Creation of two EC2 instances and how to establish ping communication - YouTube
The only difference is I used a linux image.
I setup a simple python http server on a machine (on port 8000). But I cannot access this from my other machine; whenever I curl, the program kind of waits. (It might eventually timeout but I wasn't patient enough to witness that).
However, the workaround, I figured, was that you have to add a port rule via the security group. I do not like this option since it means that that port (for the machine that hosts the web server) can be accessed via the internet.
I was looking for an experience similar to what people usually have at home with their routers; machines connected to the same home router can reach out to other machines on any port (provided the destination machine has some service hosted on that port).
What is the solution to achieve something like this when working with ec2?
The instance is open to the internet because you are allowing access from '0.0.0.0/0' (anywhere) in the inbound rule of the security group.
If you want to the communication to be allowed only between the instances and not from the public internet. You can achieve that by assigning the same security group to both the instances and modifying the inbound rule in the security group to allow all traffic or ICMP traffic sourced from security group itself.
You can read more about it here:
AWS Reference
I develop on Windows 10, so I use Hyper-V to run my Ubuntu VM. I don't want to mess around with complex networking whenever I go from a wired to wireless connection, so I just use the Default Switch.
Hyper-V sets the hostname for my development machine to nginx.mshome.net
I work on about 6 different website, so I have them all setup at hostnames like:
alpha.nginx.mshome.net
beta.nginx.mshome.net
gamma.nginx.mshome.net
For the longest time Hyper-V was pretty consistent with what IP address it assigns my VM, so I had these other hostnames just setup as static entries in my hosts file. I maybe had to go in and fix it every couple weeks, but that wasn't a big deal.
After installing the Windows 10 October 2018 Update, and the subsequent VPN x Blue Screen error that caused me to have to run netsh interface ip reset and netcfg -d, Hyper-V is now assigning a different IP address to my VM on virtually every boot.
I can't just set the VM to a static IP, because Hyper-V even changes the subnet for the Default Switch.
I tried setting up multiple network interfaces and forced dhclient to use a different hostname for each, but since they were all on the same subnet only one wanted to work on a time.
I need some kind of solution to either get Hyper-V to use and assign a consistent IP to my VM running on the Default Switch, or some kind of way to setup DNS aliases on Windows 10.
I've set this up using the Hyper-V Private Switch, using Internet Connection Sharing of my wireless connection to the Private Switch. I then just give the VMs a static IP, setup a host file entry, and go on my way. Since it's using ICS, that keeps the same subnet.
The only issue I have with this is that every so often Windows 10 forgets how to pass traffic over ICS. The cFosICS tool (https://www.cfos.de/en-us/cfosspeed/cfosics.htm) has a reset option that usually works. If not, cFosICS also lets you disable and reenable ICS via command line, so you can save a script to kick it into gear.
We are attempting to use a Cisco ASA as a VPN as well as forward traffic to two servers.
Our ISP has given us a range of IP addresses that are sequential.
154.223.252.146-149
default GW of 154.223.252.145, we're using netmask 255.255.255.240
We have the first of these, 154.223.252.146, assigned to the external interface on our ASA and it’s successfully hosting our VPN service. It works great.
The next and final goal is to have 154.223.252.147 forward https traffic to 10.1.90.40 and 154.223.252.148 forward https traffic to 10.1.94.40.
Our current blocker is our inability to get the outside interface of the asa to respond to these ip addresses.
We’ve been able to use 154.223.252.146 to forward https traffic correctly. So we know that works.
I’ve plugged my laptop into the switch from our ISP and have successfully manually assigned 154.223.252.147 and 154.223.252.148 with the default gw of 154.223.252.145 and was happily connected. So we know the IP’s are there and available, we just need to convince the ASA to respond to them and use them to forward https.
We’ve tried plugging cables from the switch into other interfaces on the firewall. This failed because the netmask overlaps with our first outside interface 154.223.252.146 255.255.255.240, Cisco hates this and doesn’t allow it.
We’ve read documentation and have heard that it’s possible to assign a range of IPs to the ouside interface by defining a vlan. We do not know how to successfully make this work and out attempts have failed.
What's the best way to accomplish this configuration with a Cisco ASA?
You don't need to assign multiple IPs from the same range to more than one interface. That doesn't work with Cisco. Instead try a static one to one NAT for your Web server and terminate your VPN traffic on the IP address assigned to the interface.
Watch this video for one to one NAT:
https://www.youtube.com/watch?v=cNaEsZSsxcg
Cisco has an active scanning technology that was enabled on this ASA. We were able to diagnose it by intermittent bad behavior. After troubleshooting long enough we realized that some of the behavior couldn't be consistent with the changes we were making. So we started looking for things that the firewall would be trying to do by itself. That ended up helping us narrow it down. Disabling active scanning allowed our external vlan configurations to work. Now moving on to tightening up the configs.
I am developing a networked application that runs on a few different computers on a LAN. One of the core needs is for the app to maintain a list of peers on the LAN with which it has communicated in the past, so that it can restore previous sessions. The naive solution would be to just remember the IP and store it in a table, but what happens when the IP of a peer changes?
Instead, I thought I'd store the hostname of the peers so even if the IP changes they will still be reachable via their hostname. (I know hostnames can change as well but that is good enough).
So my question is what exactly is needed to make hostname resolution work on a LAN with mixed Windows/Mac/Linux clients?
Without the use of a central authority the only reliable way to achieve this is through the use of zerconfiguration name resolution. This means that without a multicast router you will only be able to dynamically resolve peers on the same subnet as the resolving host. You could use something like bonjour for mac, netbios or ssdp for windows or avahi for linux but you can't assume that these are enabled. I may be overlooking some more popular protocols that perform this function well but I would personally throw together a quick udp broadcast name resolution protocol for your application. Take a look at these for some more ideas:
Zeroconf Name resolution
Universal local network name resolution method without DNS?
http://en.wikipedia.org/wiki/Zero_configuration_networking#Name_resolution
http://en.wikipedia.org/wiki/Broadcast_address#IP_networking
I would pick a specific udp port to listen on (lets say 12000) and then when you're ready to resolve hosts send a "hello" udp packet out to 255.255.255.255 on port 12000 and all of the other hosts on your network running your app should reply with a packet containing their hostname, possibly other information.
In short: How to reliably discover a server running somewhere on a (presumably multi-segmented) local area network with zero client configuration
My client application has to locate the server application without knowing the server IP address. It has to work on a local LAN that may be split into segments with hubs or other switching devices.
I already have a working solution, but it is a bit cumbersome to get it working on multi-segment networks. It works as follows:
When the client starts up, it sends UDP broadcasts on its own network segment. If the server is running on the same segment, it works without any issues - the server responds with the appropriate messages.
If the server and client are running on networks separated by a hub / switch that won't forward UDP (the most likely case), then I have a server instance running on each segment, and they forward client requests to each other via TCP - but I need to configure this for the server instances (simple, but still a pain for tech support.) This is the main problem that I need to address. There are sites where we have hundreds of clients running on 5 or 6 separate segments.
The problems I'm facing:
1. Although my application installer enables the appropriate ports on the firewall, sometimes I come across situations where this doesn't seem to happen correctly.
2. Having to run multiple server instances (and therefore configure and maintain them) on hub/switched networks that won't forward UDP
Finally I need a solution that will work without maintenance on a minimal Windows network (XP / 2000 / Vista) that probably doesn't have Active Directory or other lookup services configured.
I don't want to tag on any runtime stuff for this - should be able to do it with plain VC++ or Delphi.
What approaches do commercial apps usually take? I know that SQL Server uses a combination of broadcast and NetBEUI calls (I may be wrong about this).
Thanks in advance.
You have a few terminology issues:
Where you say "network segment" you appear to mean "IP subnet". Devices on the same network segment can see the same IP broadcasts.
Where you say "hub/switch" you appear mean "IP router".
Where you say "won't forward UDP", the problem is actually "won't forward IP broadcasts".
Once we get past that, you have a few options:
Your servers could register themselves under a well-known name in DNS, if you have a DNS server that allows dynamic DNS updates. You should probably use a SRV record as specified in RFC2782. The clients then do a DNS lookup to find the server(s).
You could statically assign your server(s) well-known names in the organisation's DNS, perhaps with a SRV record as with the previous option.
Your servers could join an IP multicast group, if your routers support IP multicast. The clients then send their initial discovery request as a UDP packet to the (pre-ordained) multicast address.
If you have domain server, I would go with small service on it. You can connect with other services to it and use it as distribution point.
Why domain server? It is relatively easy to find it's name (DsGetDcName).
Other choices would include DHCP server, DNS server or something of that kind that needs to be filled by maintenance staff anyhow.