Newest questions tagged networking - Super User © superuser.commost recent 30 from superuser.com2018-07-19T23:23:04Z on a domain workstation when accessing a network share © superuser.comDane Westdyk<p>This is the first time I've ever posted a question on any blog, but I'm at my wits end. I have a domain with about 50 users. I have one system that when trying to access a file share on a server in the domain, it takes an extraordinary amount of time to load, but eventually will, if you just let it do it's thing. It doesn't matter what profile I log in with (user or admin) the problem is the same. </p><p>I took the system off the users desk and connected it at my desk. Everything works fine. Files load quickly. So I thought, it was something on that network port. To test, I brought a different system to that users desk and connected it. Oddly, the connection to the shares was fast and loaded quickly on both a user and admin profile. I replaced the users system and the problem returned. </p><p>I can access the internet no problem, no latency. I can ping the server at less than 1ms. I flushed the DNS. I cleared the ARP. I updated everything. I tried in Safe Mode. I disabled Add-ons. I added the server to the host file. I don't know what else it could be.</p><p>Why does it work at a different network jack and why does a different system work on that jack?</p><p>No one else has issues.</p><p>Windows 7 and Server 2012.</p><p>Any help is greatly appreciated. </p> WSUS administration console was unable to connect to the WSUS Server via the remote API © superuser.comHunter Robertson<p>I'm trying to implement WSUS on the school's server to reduce load on our outgoing internet connection. After installing it and running into an issue (no clients would register) and rebooting the system, I am now getting an error advising me to "try restarting IIS, SQL, and the Update Services Service" because the The WSUS administration console was unable to connect to the WSUS Server via the remote API. The full log is below. I've tried various solution on other forums, such as increasing allocated RAM, increasing the fail timeout and error maximums, and reinstalling WSUS completely.</p><pre><code>The WSUS administration console was unable to connect to the WSUS Server via the remote API. Verify that the Update Services service, IIS and SQL are running on the server. If the problem persists, try restarting IIS, SQL, and the Update Services Service.The WSUS administration console has encountered an unexpected error. This may be a transient error; try restarting the administration console. If this error persists, Try removing the persisted preferences for the console by deleting the wsus file under %appdata%\Microsoft\MMC\.System.IO.IOException -- The handshake failed due to an unexpected packet format.SourceSystemStack Trace:at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)at System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)at System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)at System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)at System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)at System.Net.ConnectStream.WriteHeaders(Boolean async)** this exception was nested inside of the following exception **System.Net.WebException -- The underlying connection was closed: An unexpected error occurred on a send.SourceMicrosoft.UpdateServices.AdministrationStack Trace:at Microsoft.UpdateServices.Administration.AdminProxy.CreateUpdateServer(Object[] args)at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.GetUpdateServer(PersistedServerSettings settings)at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.ConnectToServer()at Microsoft.UpdateServices.UI.SnapIn.Scope.ServerSummaryScopeNode.get_ServerTools()'</code></pre> a Windows folder with a Mac computer through a network © superuser.comRafael Pires<p>I have a Windows computer (which has the files I want to share) that is inside a domain. I want to share a folder on the Windows computer with a Mac that is outside of the domain but on the same internet network. is it possible?</p><p>If yes, how?</p> camera causing network driver buffer trashing / memory congestion? © superuser.comVroomfondel<p>We are running a high-res camera on a reserved, single 1Gb Ethernet port, connected to a Windows 10 machine. We let the camera run on Auto-triggering and so it takes and sends images as fast as it can - at least this is what I deduce from the observed network traffic: as soon as we start the camera, Ethernet utilization goes up to ~580Mb received on the Windows machine.</p><p>BUT: our image processing software (HALCON) does not grab every frame the camera sends. This isn't an issue for our task (nearly static scene, we only need a new frame when we have processed the old one after ~200 milliseconds) were it not for the fact that the attempt to grab the next image results in completely arbitrary delays, lasting from ~100 milliseconds to 20-30 seconds. The suspicious thing is that the first number of grabs runs smoothly and only afterwards we stumble around with unpredictable waiting times. Is it possible that these delays come from the application/network driver/os (which one I don't know) wading through the received data stream and throwing out aged packets? Is there a way to restrict Windows on one network interface to a few MB of receive buffer so that it wouldn't even try to build up many hundred MB of data stream which is thrown out anyway?</p><p>Thanks in advance</p><p>PS: Sorry for the layman language, my background is embedded engineering.</p><p>PPS: Windows firewall is disabled for all ports</p> the ARP standard forbid a switch to answer for another machine? © superuser.comBadSnowflake<p>Consider a setup, where there are 2 switches with some devices behind each of them. They have the same sub net, so a broadcast goes to both parts of the network. </p><pre><code>|PC1|PC2|PC3|||Switch1| Subnet:| Broadcast: | FFFF.FFFF.FFFF|Switch2|||PC4|PC5|PC6|</code></pre><p>So, if Switch2 knows the MAC of PC4 and receives an ARP request from PC1, would Switch2 be allowed to answer, using it's own ARP table? I know that they don't, I traced this through a few simulations in Cisco Paket Manager. But is it the protocol that forbids it, or are the switches just not smart enough?</p> used Cloudflare - where is Cloudflare error message coming from? © superuser.comAlien Technology<p>I am trying to understand why we are getting a Cloudlare error when we've never used Cloudflare.</p><p>We have a Peplink 210 which has two WAN ports and serves as our firewall and router. One WAN port goes to Cox, the other is a new AT&amp;T line. Both have static IP addresses.</p><p>Traffic on the Cox line works as expected. If port 80 is forwarded to a server and we browse to that external IP address, we see the website and if port 80 for that IP is not forwarded, the browser times out.</p><p>If I forward port 80 on one of the AT&amp;T addresses to a web server I can browse to the site using the IP address. But if the port is not forwarded, instead of timing out we get this error:</p><p><a href="" rel="nofollow noreferrer"><img src="" alt="enter image description here"></a></p><p>DNS is not involved since I'm going directly to the IP. Where is this message coming from?</p> able to route between bridges © superuser.comAlvaro<p>i have a virtual machine with 2 network interfaces (eth0 and eth1). Each interfaces is connected to a different bridge so i can connect eth0 to another virtual machine and eth1 to my physical ethernet. Im not able to route traffic from eth0 to eth1. Traffic comes from to network. My route to do this is:</p><p> dev eth1</p><p>I'm able to see traffic in the virtual ethernet that connects eth0 to the bridge but no traffic is routed to eth1 and the other bridge. What am i missing here?</p><p>Thanks in advance.</p> wired LAN for printer and wireless for internet © superuser.comBrad<p>I have a small office, used one day a week, that does not have internet, so everyone connects using their phone as hot spots. We have a printer everyone needs to share. I want to set up the printer on a wired network (small unmanaged switch) but still be able to use wireless for internet. How can I set this up to use both connections, and not have to change adapter settings for everyone each week?</p> host hotspot with website © superuser.comCoco Nut<p>I apologize if this has already been asked but I couldn't find it.</p><p>I would like to use my windows 10 computer as a hotspot where all requests (like a McDonald's login page) redirect to a website also hosted on the computer.</p><p>I have been able to create a hotspot with netsh hostednetwork commands:</p><pre><code>netsh wlan set hostednetwork mode=allow ssid="Test network" key=netsh wlan start hostednetwork</code></pre><p>And also with programs such as Hotspot creator.</p><p>Now I just need the webpage redirect. (All I have is the HTML code for the website)</p><p>Thanks in advance, and please treat me like an idiot who doesn't understand computers just in case.</p>'s network adapter connecting at 100 Mbps instead of 1 Gbps © superuser.comIgor Yavych<p>Some weird stuff started happening with my wife's laptop. Instead of 1 Gbps she was getting before, at some point of time, she started getting 100 Mbps.It's not a problem with router nor it is a problem with a cable. My PC is getting 1 Gbps and I tried using that cable and port on the router for laptop and it was still getting 100 Mbps. I've tried setting link speed to 1 Gbps but it didn't help either. What are other possible causes for such a problem?</p> Windows 8.1 need to set static IP when connect to wireless © superuser.comotto wang<p>I have only one Windows 8.1 PC at home. When it connects to wireless and set it to get IP automatically, it can get IP but no internet accessible, and if I set it as static IP(I specify the static IP to be as the same as the IP that it gets automatically), and it works fine now(can access the Internet normally).</p><p>What can do for this issue? Thanks.</p> Nintendo Switch From Accessing Internet [on hold] © superuser.comuser904966<p>Downloading system or game updates to the Nintendo Switch can result in the irreversible removal of glitches in certain games (i.e., Frog Jump in Super Mario Odyssey). I want a way to guard against accidentally connecting my Switch to the internet and downloading updates.</p><p>Airplane mode can only be activated, thus is presumably only functional, while the Switch is in handheld mode. Is there a way lock the Switch out of internet access, through the Switch, the ISP (Xfinity) admin tool, or any other means? Solutions that prevent access to all networks would obviously be preferable to locking it out of specific networks (i.e., in case the neighbor's wifi suddenly pops into range).</p> network setup on kali © superuser.comAhmed Allam<p>i am trying to learn to use kali linux.<br>i installed it on vmware and installed win7 32bits and win xp s1 to make 2 host only networks..<br>i struggled with udev to properly name my network interfaces..<br>i still see network manager showing other names for my interfaces but now at least i see my interfaces names i want in parentheses beside the network manager names of interfaces..<br>i didnot dig more to fix interfaces names and felt enough with my intended names in the parantheses.<br>i then started to make the network giving all systems static ips for both networks.<br>i read that i need samba so i installed it then made new user for win7-32 and after this i enabled sharing on win7-32 and could open shared folder on win7-32 from kali using connect from network and also open kali shared folder from win7-32.<br>so i think this network is properly set.....but i have been trying to see the win7-32 in "windows network" tab of files manager in kali but it is always empty?!!!!<br>how can it be empty and i can see them with smbtree and open the shared folder of win7-32 from kali?!!!<br>what else should i do?<br>by the way , i added ubuntu 16.04 64bit and its file system sees the network and all pcs inthe network.<br>i don`t know if ubntu use nautilus or other file manager but i can not find any samba folders in its etc.<br>i find one smb.conf i usr/share/doc/nautilus-share/examplesi think it is just example.<br>so how ubuntu see windows systems without samba??<br>and how can i transfer this behaviour to kali<br>thaks</p> one Windows 10 computer join the network of another Windows 10 computer © superuser.comOtto Abnormalverbraucher<p>I have a setup of a tower PC and a Notebook both using Windows 10 and both connected via cable to my router. Previously they were in the same home group and thus able to find each other in the Explorer.</p><p>But now that the last Windows 10 update has removed the home groups neither of them can find the other. I have checked the network detection and file- and printer sharing options and they're all set up properly, meaning <code>private</code>, <code>guest and public</code> are both active. Sharing public folders in the <code>all networks</code> section is disabled, though, but that shouldn't cause trouble.</p><p>Now, I think the problem is that both of the PCs are contained in their own network. In the <code>ethernet</code> menu item in the settings I can see that my notebook is part of the <code>Todkaeppchen</code> network, while my tower PC is in the <code>Network 2</code>. Neither can find any other network and in the control panel I only have the option to create a new network, not join an existing one. So, how can I tell my tower PC to join the <code>Todkaeppchen</code> network of my notebook?</p><p>I should note that I also have a WLAN network set up named <code>Todkaeppchen</code>, which the notebook can connect to but not the tower. However, as it is set in the Ethernet section I don't think this is the root of the problem. Nothing changes whether my notebook is connected to the WLAN with the same name or not.</p> routing with systemd-networkd and a non-network-address destination results in an error: Could not set route: Invalid argument © superuser.comdevurandom<p>My machine was to act as the router for an IP address <code></code> inside a <code>/29</code> subnet with gateway <code></code>. It would thus be physically connected to the downstream machine <code></code> on one network interface, as well as the upstream gateway <code></code> on another network interface. It would itself not have an own IP address inside this network.</p><p>I set up the route to <code></code> on the downstream network interface (not shown here) and then tried to configure the upstream network interface as follows:</p><pre><code>[Match]Name=enpXsY[Network]Address=[Route]Destination=</code></pre><p>This results in an error: <code>Could not set route: Invalid argument</code>.</p> routing with systemd-networkd via a gateway results in error: Could not set route: Network is unreachable © superuser.comdevurandom<p>I run several LXC containers on my machine, some of which have their own IP address outside a network shared with the host. This IP address, as well as the corresponding network mask and gateway was provided to me by my ISP. I am using systemd 238 and tried following configuration [1]:</p><pre><code>[Match]Name=enpXsY[Network]Address=[Route]Destination=</code></pre><p>In the <code>systemd-networkd</code> logs I see following error: <code>Could not set route: Network is unreachable</code>, but I cannot really explain this. If I do not specify a gateway, the kernel can route to this network just fine. Thus I would assume it would also be able to route the traffic to the gateway through this same interface. This does not even work, if I specify a route with <code>Destination=</code> before the route to <code></code>, in order to take the kernel by the hand and explain how to reach that network.</p><p>[1]: I translated the actual IP-addresses into similar addresses in non-routed networks for privacy reasons.</p> remove HyperV vEthernet (Default Switch) © superuser.comChris<p>Basically, this: <a href="">How to remove all the vEthernet (Default Switch) once and for all?</a></p><p>Except, I removed hyperV and the Containers feature, and all that happened was that the NIC reported as disabled. But it was still there. Then I reinstalled hyperV and it created a <strong>second</strong> one. Removing HyperV disabled, but did not remove the second one. </p><p>I removed it from the registry manually (see third post here: <a href="" rel="nofollow noreferrer"></a>) and that made exactly no difference. </p><p>So my question is, short of resetting my laptop, how can I make this stupid thing go away? It's screwing up my networking (auto-switch between WiFi and Ethernet doesn't work anymore)</p><p><strong><em>Edit:</strong> for clarification, my end goal, here, is to have (a) Hyper-V removed (uninstalled) and (b) remove the (now unnecessary and unwanted) Hyper-V switches that remained after Hyper-V was uninstalled.</em></p> Multi-subnet SOHO to IPv6 © superuser.comJoeWalt<p>I am migrating my multi-subnet ipv4 home network to ipv6. Unfortunately, I am with an Internet provider who supplies only one non-but-mostly-static GUA/64 address. With or without Internet, I want ipv6 internally including my own DNS and DHCP and router advertisement services. My question(s) concern the best strategy to set this up with Internet access considering the following facts as I understand them:</p><p>A) ipv6 addresses are 48 bits global routing prefix, 16 bits subnet-id and 64 bits host-id, meaning my ISP has already precluded use of more than one network with their GUA unless I subnet into the host-id portion but doing so will break EUI-64 stateless autoconfiguration. </p><ol><li>Should I care since I will have my own stateful configuration (RA(s),DHCP,DNS)?</li></ol><p>B) ULA's can be used to create internal networks that are not globally routable. Any interface can also be assigned multiple addresses, including both a ULA and GUA.</p><ol><li>Would doing so not imply two ipv6 networks per host, one internally routable and one externally routable?</li><li>Any cordoning done by route, firewall or other on the ULA based nets would be effectively undone if I go back and add GUA's based on the single ISP provided net, correct?</li><li>Would the default route for each host not need to be the external router internal GUA address with all ULA-based networks added to each routing table?</li><li>Can dhcpv6 push routes and even if it can, will most random vendor devices like tablets or phones necessarily use them?</li></ol><p>C) NAT66 is eschewed in most docs</p><ol><li>given the not-quite-static nature of the ISP GUA and the other issues as noted, wouldn't the overall best answer be to use ULA's internally and NAT at the external router?</li></ol> would happen if I increase the ping packet size © superuser.comBerkay Makas<p>I am a newbie to this networking thing and I wonder something that if I increase the ping size to 65.600, how does it affect the internet traffic? </p><pre><code>ping –1 65500 [IP address]</code></pre> does Huawei Netcube appear as DNS server to a MacBook © superuser.comDrux<p>I'm operating a MacBook (with macOS 10.13.6) at home. My internet connection is thru a Huawei Netcube E5180s-22. </p><p>When I inquire my DNS configuration with <code>scutil --dns</code> I get this (<code></code> is the private IP address of the NetCube on the WLAN):</p><pre><code>resolver #1nameserver[0] :[1] :</code></pre><p>Now I am wondering: does the NetCube run some kind of DNS server, or is this report an artifact of it performing NAT (or similar)?</p> users connected to the same non-open (e.g. WPA-PSK) WiFi see each others traffic? © superuser.comuser111854<p>I understand that users connected to the same open WiFi can see each others traffic, since it is send in plaintext; this even holds for users not connected to the WiFi.</p><p>However, Wikipedia states that the encryption key in WPA-PSK is derived from the passphrase, that all users must know to connect to the WiFi. So, all users derive and use the same encryption key?</p><p>In other words, all users that connect to the same WPA-PSK WiFi can see each others traffic, and only users not connected to the WiFi are unable to see the traffic?</p><p><a href="" rel="nofollow noreferrer"></a></p><blockquote><p>Each wireless network device encrypts the network traffic by derivingits 128-bit encryption key from a 256 bit shared key. This key may beentered either as a string of 64 hexadecimal digits, or as apassphrase of 8 to 63 printable ASCII characters.[16] If ASCIIcharacters are used, the 256 bit key is calculated by applying thePBKDF2 key derivation function to the passphrase, using the SSID asthe salt and 4096 iterations of HMAC-SHA1.[17] WPA-Personal mode isavailable with both WPA and WPA2.</p></blockquote> an IP to a computer © superuser.comFrank Fileccia<p>I have a network with 4 computers. Three are connected by cables to the WIFI Router, one connects by wifi</p><p>I have a static IP from my provider</p><p>The problem I have is that every time the router is rebooted it assigns new IP's to each computer. On three of them it's not a problem but it's a big problem on the fourth because I has to allow external access to a mysql database</p><p>In the router I locked the router assigned IP to that computer in Forwarding</p><p>But of course, everything screws up when the router is rebooted and it assigns new internal IPs</p><p>How can I lock the network IP on that specific computer so it doesn't change every reboot? </p><p>It would be nice if all 4 were locked, but the one urgently has to be locked</p> WiFi packets on a public hotspot © superuser.comjohn<p>To decrypt 802.11 header in Wireshark, you must know the WPA password.</p><p>Now, for example, there is a network which when clicked takes you to a login page where every user on the network has a username and a password. So, it's an open network but redirects you to a page with a login screen.</p><p>If I decrypt the 802.11 packets with wireshark with my username and password, can I see all the other packets, like other people that are browsing without knowing their username and password? Like, instead of seeing "protocol:802.11", can I see "http,tcp"? Even though it's all on the same network but everyone has their own password? If, what i am saying is wrong, is there a way to decrypt 802.11 headers without knowing the WPA password?</p><p>I am not sure how much sense it made but if some part does'nt make sense, please ask.</p> ethernet cable to TP-W8901G breaks web page © superuser.comfakechek<p>I'm experiencing a strange problem and would really appreciate some help from you.</p><p>I recently moved into a new apartment that has a very outdated internet setup: 20 MBit connection with a TP-Link TP-W8901G modem/router combo. With me I brought a Synology DS216j that is quite important for me as I use it for backups and data storage. Apart from the WiFi being terribly slow, I noticed that when plugging in the NAS to the modem/router (normal ethernet cable) I can no longer access the modem/router through it's web interface (<code></code>). Even when removing the cable it still won't work until I hard-reset the modem/router. Last night I was testing with my laptop (MacBook) and an ethernet adapter if the problem could be the Synology but the same thing happened. Strangely enough, it seems that the cable connection works since I was still connected to the internet, yet no modem/router under <code></code> (I double-checked the address). I need to configure the modem/router after connecting the Synology in order to assign it a static IP address.</p><p>Does this sound like a problem of the modem/router to you? Do you have an idea how to test it?</p><p>Note 1: The web interface becomes unavailable both for wired and wireless connections.</p><p>Note 2: I already checked this thread here (<a href="">Can&#39;t access login page of TP-Link router (TD-W8910G)?</a>) but it didn't help.</p><p>Unfortunately, replacing the modem/router is not an option at the moment.</p><p>Thanks a lot!</p> is there a "sadpc" in my Network? [on hold] © superuser.comMaxis Jaisi<p>I clicked on the Network icon beside my Macintosh HD icon, and in it there's something called "sadpc". What is it? Does it mean I've been hacked? What should I do?</p> KVM migration b/w two machines while keeping bridged guest IP static © superuser.comamir mohamad hatami<p>On each of two Ubuntu PCs, I installed KVM and created some VMs. All the VMs on each PC should see each other, so I could not use the private IP assigned to them by KVM and AFAIK that requires creating a bridge so their IPs are visible to each other. The two machines are connected to each other with a router.</p><p>Now I want to migrate one of these VMs from one side to another side. But the IP address which is defined at first should be kept constant. Is it possible to do a live migration with these conditions? If not, or you know other better ways to do this, please advise. </p> Network in Linkit 7688 (OpenWRT) © superuser.comUgur Akgul<p>I'm new to networking and openWRT. I just compiled an openWRT version but the wifi module was absent. To transfer a new firmware i tried to work around the network settings and get the ethernet to the master mode. But doing so also cancelled my wifi connection. Now i want to make this configurations permanent (in case of broken firmware again to somehow connect w/ SSH) but with a viable internet connection through wifi. My config files and <em>ifconfig output</em> are below. Also i am using an <em>openWRT 3.18.23</em> kernel.</p><pre><code> etc/config/network :config interface 'loopback'option ifname 'lo'option proto 'static'option ipaddr ''option netmask ''config globals 'globals'option ula_prefix 'fd6b:f1eb:9a25::/48'config interface 'lan'option force_link '1'option macaddr '9c:65:f9:23:a9:cf'option type 'bridge'option proto 'static'option netmask ''option ip6assign '60'option ipaddr ''config switchoption name 'switch0'option reset '1'option enable_vlan '0'config interface 'wan'option ifname 'eth0'option proto 'dhcp'option macaddr '9c:65:f9:23:c3:33'etc/config/wireless :config wifi-ifaceoption device 'radio0'option network 'wwan'option mode 'sta'option ssid 'myssid'option encryption 'psk2'option key 'mykey'option disabled '0'config interface 'wwan'option proto 'dhcp'config zoneoption name 'lan'option input 'ACCEPT'option output 'ACCEPT'option forward 'ACCEPT'option network 'lan wwan'config wifi-device 'radio0'option type 'ralink'option variant 'mt7628'option country 'TW'option hwmode '11g'option htmode 'HT40'option channel 'auto'option disabled '0'config wifi-iface 'ap'option device 'radio0'option mode 'ap'option network 'lan'option ifname 'ra0'option encryption 'none'option ssid 'LinkIt_Smart_7688_23C333'option seq '1'config wifi-iface 'sta'option device 'radio0'option mode 'sta'option network 'wan'option ifname 'apcli0'option led 'mediatek:orange:wifi'option encryption 'psk2'option ssid 'XXXXX'option key 'XXXXX'option disabled '0'config wifi-device 'radio1'option type 'mac80211'option channel '11'option hwmode '11g'option path 'platform/10300000.wmac'option htmode 'HT20'option disabled '1'config wifi-iface 'default_radio1'option device 'radio1'option network 'lan'option mode 'ap'option ssid 'OpenWrt'option encryption 'none'ifconfig :br-lan Link encap:Ethernet HWaddr 9C:65:F9:23:A9:CF inet addr: Bcast: Mask: addr: fd6b:f1eb:9a25::1/60 Scope:Globalinet6 addr: fe80::9e65:f9ff:fe23:a9cf/64 Scope:LinkUP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1RX packets:0 errors:0 dropped:0 overruns:0 frame:0TX packets:336 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:34384 (33.5 KiB)eth0 Link encap:Ethernet HWaddr 9C:65:F9:23:C3:33 inet6 addr: fe80::9e65:f9ff:fe23:c333/64 Scope:LinkUP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1RX packets:0 errors:0 dropped:0 overruns:0 frame:0TX packets:1425 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:479164 (467.9 KiB)Interrupt:5 eth0.1 Link encap:Ethernet HWaddr 9C:65:F9:23:A9:CF inet6 addr: fe80::9e65:f9ff:fe23:a9cf/64 Scope:LinkUP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1RX packets:0 errors:0 dropped:0 overruns:0 frame:0TX packets:29 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:6937 (6.7 KiB)lo Link encap:Local Loopback inet addr: Mask: addr: ::1/128 Scope:HostUP LOOPBACK RUNNING MTU:65536 Metric:1RX packets:5952 errors:0 dropped:0 overruns:0 frame:0TX packets:5952 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:0 RX bytes:404736 (395.2 KiB) TX bytes:404736 (395.2 KiB)ra0 Link encap:Ethernet HWaddr 9C:65:F9:23:C3:33 inet6 addr: fe80::9e65:f9ff:fe23:c333/64 Scope:LinkUP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1RX packets:78158 errors:0 dropped:0 overruns:0 frame:0TX packets:5995 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:1000 RX bytes:16156893 (15.4 MiB) TX bytes:0 (0.0 B)Interrupt:6</code></pre><p>I am looking for a way to learn and accomplish this. Either there is no good documentation on this or i simply don't understant what i am reading. Any help/comment/suggestion would be appreciated.</p> on network cards - why it's used? © superuser.comLapsio<p>I noticed that plenty of enterprise grade network adapters use weird metal "fences" near pci-e connector. I think it's kind of shield isolating NIC from motherboard but to be honest... Why do we need such thing? NICs operate on digital data and don't really seem to be that much vulnerable to electromagnetic noise so what's purpose of those metal fences? I'm talking about piece of metal near the edge of card, like one here:</p><p><a href="" rel="nofollow noreferrer"><img src="" alt="Network card with shield"></a></p><p>Also some of them are placed a bit above PCB so it makes even less sense to me if it's supposed to be EM shield.</p> NAT for isolation © superuser.comRichard<p>I have an existing network but want to provide WiFi in a room that is isolated from my main network. I thought a simple WiFi router would be good for the job as the NAT will prevent access to anyone on WiFi to my main network.</p><p>My main network is 192.168.1.X and I have configured the second router to 10.0.0.X network and its WAN is on DHCP (on However, while connected to second router (, I can still access my main network ( n so on).</p><p>Any idea how to prevent that from happening?</p><p>P.S. Searching on internet didn't help so far as 99% of results are the other way around i.e. accesing primary network behind second NAT.</p><p>P.S.(2) I know the proper way to do this is via VLANS and multiple SSIDs on APs but as you've guessed its only for guests and I need a simple inexpensive way to do that.</p> to connect two virtual machines with accessible private IP address © superuser.comamir mohamad hatami<p>I am trying to have some VMs on two Ubuntu hosts using KVM (two seperate machines).</p><p>I want all these VMs to be accessible with their private IPs (or public IPs). I know the local IPs of the VMs can not be used since they are behind NAT. Kindly let me know the simplest options and requirements for this purpose. </p><p>To be more specific:</p><ol><li><p>How they should be physically connected (a cable, a hub, a router, etc..)? The two machines are currently connected to a WIFI router. But since WIFI routers are sometimes busy and have high latency, I am looking for a better option.</p></li><li><p>How should the virtual machines be configured, so their IP addresses would be visible to others?</p></li></ol><p>Thanks.</p>