Server Fault Stack Exchange
Server Fault Stack Exchange

Questions tagged [netmask]

41 questions
2
votes
1 answer

Why do I lose network connectivity for a virtual machine outside /24?

I have a bunch of virtual machines (Ubuntu Server 14.04) hosted on a single real server (Ubuntu Server 14.04 with KVM). The number of virtual machines grow, and I'll soon have more than 254 of them. To test, I changed in /etc/network/interfaces of…
Arseni Mourzenko
  • 2,275
  • 5
  • 28
  • 41
2
votes
2 answers

Hazards of increasing network size by changing the netmask

We are running a small network with address range 192.168.0.0/24. So we only have 254 IPs available. We want to increase this range slightly, to allow more hosts in the network. So if I change the network to 192.168.0.0/23, that should give us 256…
ssin
  • 53
  • 2
  • 5
1
vote
0 answers

Is it a bad idea to use /128 subnet when a machine is alone in a /64 subnet?

Example: I got a virtual machine with its own /64 subnet and the default gateway is reachable via a link-local address. In this subnet there is only one machine, the virtual machine itself. The machine is reachable when I configure a single IPv6…
netlok
  • 11
  • 1
1
vote
1 answer

Connection through VPN

I'm a Java Developer and for a few weeks I'll be in charge of the network as well. A client of ours wants a VPN connection to his network which I already mounted (Using a TP-link router to stablish the IPSEC Tunnel LAN-to-LAN). Our network:…
Javier
  • 13
  • 2
1
vote
1 answer

Bridged network setup with gateway not in netmask

i'm currently stuck at setting up the bridged networking on a dedicated server to allow the KVM-guests to use ips from an extra subnet. As far as i know, the address, broadcast and gateway must always be in range of the netmask. My original network…
Silom
  • 111
  • 3
1
vote
1 answer

Solaris spoof mac impossible

I need to spoof the MAC address in Solaris 10, running in a ESXi VM. The MAC I need is outside the range permitted by vSphere. So I add an "ether" entry to /etc/hostname.e1000g0 so the file says abchost01 ether 1:2:3:4:5:6 and reboot. To my horror,…
Jepper
  • 366
  • 1
  • 4
  • 13
1
vote
1 answer

255.255.255.255 broadcast address meaning

Lets suppose we have a computer with three NICs: NIC_1: 172.16.1.1/24 NIC_2: 192.168.1.1/24 NIC_3: 103.55.34.32/24 We send a packet with the destination IP address being 255.255.255.255. 1) if the default gw is on the 103.55.34/24 network, will the…
colemik
  • 759
  • 1
  • 12
  • 24
1
vote
1 answer

Confused about routing and netmasks

I'm having some issues with OpenVPN and multiple VPNs. Not earth shattering, but after bringing up a combination of VPNs I didn't intend to I've ended up in a situation I don't understand. Looking at the following output; C:\Users\craig>route…
Craig Graham
  • 183
  • 3
  • 7
1
vote
2 answers

changing netmask of loopback interface

I can change netmask of loopback inteface (usually lo interface has 127.0.0.1/8): pi@raspberrypi:~ $ ifconfig lo: flags=73 mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 …
mastupristi
  • 111
  • 2
0
votes
2 answers

How to change Google compute instance primary network device eth0 netmask /32

When I create an instance in the default VPC, and check ifconfig, it says netmask is /32, as shown below: eth0: flags=4163 mtu 1460 inet 10.138.0.2 netmask 255.255.255.255 broadcast 10.138.0.2 …
alexfvolk
  • 164
  • 2
  • 10
0
votes
1 answer

Adding single IP as /32 working well, but not by adding /27 mask

i've got additional /27 IP's subnet for my Debian server. I was trying multiple configurations, but without success on adding whole subnet. Running ip addr add 231.231.231.0/32 dev eth0 Working well, and i can ping the following IP without any…
Gordon Freeman
  • 3
  • 1
0
votes
1 answer

Does it make sense, in terms of performance, to have more than one subnet on the same switch?

We're on a /20 subnet (255.255.240.0), which means 4k addresses. A consultant told us that moving to a subnet with less addresses might increase performance. This network is heavy in file transfers and block-level SAN. Does the creation of a new…
Zopiro
  • 51
  • 1
  • 1
  • 4
0
votes
3 answers

RHEL with two interfaces - Can't ping/ssh into second interface

I have a RHEL Server 'foo' with two interfaces: eth0: inet addr:172.16.15.75 Bcast:172.16.15.95 Mask:255.255.255.224 eth1: inet addr:172.16.15.242 Bcast:172.16.15.247 Mask:255.255.255.248 root@foo # netstat -nr Kernel IP routing…
jdmuntz
  • 17
  • 1
  • 3
0
votes
1 answer

How can I tell what's happening to my packets?

I'm trying to bring up a little box on my network. I just reflashed the firmware and it's supposed to come up as 192.168.1.1 by default. My router is a DSL modem at 192.168.0.1; it usually uses a netmask of 255.255.255.0, so I can't talk to the new…
Adam Bliss
  • 131
  • 5
0
votes
2 answers

Unreachable host inside network

I'm trying to use some unusual network configurations. Host1 (internet gateway): IP: 192.168.0.1 Mask: 255.255.0.0 Host2: IP: 192.168.1.10 Mask: 255.255.0.0 Default gateway: 192.168.0.1 I can't ping the Host1 from Host2. Did I miss something…
Marcus
  • 111
  • 3
1
2
3