Hello everyone,
 
I have followed this guide to enable my Windows 10 guest to reach my Arch Linux host: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Host_Configuration_and_Guest_Installation_Guide/App_Macvtap.html
 
My VM now has 2 NICs: 
- macvtap (VEPA)
- virtual network 'isolated'
 
I have statically assigned the IP 192.168.254.2 to my guest. The host's IP is 192.168.254.1. The interface it is using on the host is virbr1.
 
I am able to ping the host from the guest and vice versa, so the network connectivity seems to be generally working. To control my VM I'd like to use Synergy which I have already set up and tested successfully once with the VM as the Server, but never since. When I try to connect the Synergy client from the host to a server running on the guest, I get the error "failed to connect to server: address not found for: 192.168.254.2".
 
This is the result of nmap:
[root@thearch ~]# nmap 192.168.254.0/30
 
Starting Nmap 7.12 ( https://nmap.org ) at 2016-05-14 17:14 CEST
Nmap scan report for 192.168.254.2
Host is up (0.0010s latency).
Not shown: 995 filtered ports
PORT      STATE SERVICE
135/tcp   open  msrpc
139/tcp   open  netbios-ssn
445/tcp   open  microsoft-ds
5357/tcp  open  wsdapi
24800/tcp open  unknown
MAC Address: 52:54:00:96:11:A9 (QEMU virtual NIC)
 
Nmap scan report for 192.168.254.1
Host is up (0.0000040s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
53/tcp open  domain
 
Nmap done: 4 IP addresses (2 hosts up) scanned in 5.16 seconds
 
I also did nmap from a non-root user:
[christopher@thearch ~]$ nmap 192.168.254.0/30
 
Starting Nmap 7.12 ( https://nmap.org ) at 2016-05-14 17:17 CEST
Nmap scan report for 192.168.254.1
Host is up (0.000073s latency).
Not shown: 999 closed ports
PORT   STATE SERVICE
53/tcp open  domain
 
Nmap done: 4 IP addresses (1 host up) scanned in 1.26 seconds
 
As you can see, the host 192.168.254.2 is only found when running nmap with root, not with my other user. Pinging the guest still works however.
 
I suspect this is the core of the issue, but I don't know how to solve it. Any suggestions are appreciated.
 
Thanks,
Christopher Mühl