Frequently Asked Questions About Linux / UNIX » Networking http://www.cyberciti.biz/faq Every answer asks a more beautiful question. Fri, 03 Feb 2012 22:38:32 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 Gnome Network Manager VPN Tab Disabled ( Greyed out )http://www.cyberciti.biz/faq/deiban-ubuntu-linux-networkmanager-pptp-cisco-vpn-tab-disabled/ http://www.cyberciti.biz/faq/deiban-ubuntu-linux-networkmanager-pptp-cisco-vpn-tab-disabled/#comments Thu, 26 May 2011 12:08:20 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10574 I've the NetworkManager service is installed and started under Linux desktop. The applet is running. The NetworkManager can display available network hardware and wireless networks. But, I'm unable to add VPN support as the Add tab is greyed out. I need to use both PPTP and Cisco vpn clients. How do I fix this problem under Debian or Ubuntu Linux?]]> http://www.cyberciti.biz/faq/deiban-ubuntu-linux-networkmanager-pptp-cisco-vpn-tab-disabled/feed/ 6 Linux Static IP Address Configurationhttp://www.cyberciti.biz/faq/linux-configure-a-static-ip-address-tutorial/ http://www.cyberciti.biz/faq/linux-configure-a-static-ip-address-tutorial/#comments Sat, 23 Apr 2011 22:04:00 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10354 How do I configure the Internet Protocol version 4 (IPv4) properties of a network connection with a static IP address for servers running Linux operating systems? How do I configure static IP address under Debian Linux or Redhat / RHEL / Fedora / Redhat Enterprise Linux server?]]> http://www.cyberciti.biz/faq/linux-configure-a-static-ip-address-tutorial/feed/ 3 Linux Display Ethernet Bridge Name and Informationhttp://www.cyberciti.biz/faq/linux-command-to-display-network-bridge-name/ http://www.cyberciti.biz/faq/linux-command-to-display-network-bridge-name/#comments Mon, 21 Mar 2011 05:40:16 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=10172 How do I display a list of bridges under Linux? How do I show info about the Ethernet bridge configuration in the Linux kernel?]]> http://www.cyberciti.biz/faq/linux-command-to-display-network-bridge-name/feed/ 0 Linux: Check Network Connection Commandhttp://www.cyberciti.biz/faq/check-network-connection-linux/ http://www.cyberciti.biz/faq/check-network-connection-linux/#comments Mon, 10 Jan 2011 19:50:28 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9703 How do I check network connections under Linux using command line options? ]]> http://www.cyberciti.biz/faq/check-network-connection-linux/feed/ 1 Ubuntu: SIOCADDRT: File exists Error and Solutionhttp://www.cyberciti.biz/faq/siocaddrt-file-exists-ubuntu-linux-error-solution/ http://www.cyberciti.biz/faq/siocaddrt-file-exists-ubuntu-linux-error-solution/#comments Mon, 03 Jan 2011 19:47:12 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9665 I'm typing the following command under Ubuntu Linux:
route add default gw 192.168.3.2 eth0

But it is giving me out the following error:
SIOCADDRT: File exists

How do I fix this problem?]]> http://www.cyberciti.biz/faq/siocaddrt-file-exists-ubuntu-linux-error-solution/feed/ 0 HowTo: Linux Send a Gratuitous ARPs Requests [ Networking ]http://www.cyberciti.biz/faq/linux-networking-sending-gratuitous-arps/ http://www.cyberciti.biz/faq/linux-networking-sending-gratuitous-arps/#comments Fri, 03 Dec 2010 23:02:40 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9515 How do I send gratuitous ARPs under Linux? How do I tell my DUMMY router that the IP is over here now, under Linux operating systems?]]> http://www.cyberciti.biz/faq/linux-networking-sending-gratuitous-arps/feed/ 0 IPv6 Address Examplehttp://www.cyberciti.biz/faq/ipv6-address-example/ http://www.cyberciti.biz/faq/ipv6-address-example/#comments Fri, 12 Nov 2010 21:20:36 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9331 What does an IPv6 address look like? Can you give an example of IPv6 address? How do I view an IPv6 address under Linux or UNIX operating systems?]]> http://www.cyberciti.biz/faq/ipv6-address-example/feed/ 0 Linux Network IP Accountinghttp://www.cyberciti.biz/faq/linux-configuring-ip-traffic-accounting/ http://www.cyberciti.biz/faq/linux-configuring-ip-traffic-accounting/#comments Tue, 09 Nov 2010 20:22:35 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9209 I need to know how much data are transmitted on my ppp0 network or eth0 Internet links? How do I set IP accounting by address such as 123.1.2.3 and 123.1.2.4? How do I set IP accounting per Apache virtual domain? How do I set accounting by service port (http, smtp) and protocol (tcp, udp, icmp)? How do I record how much traffic each of the clients computer is using?]]> http://www.cyberciti.biz/faq/linux-configuring-ip-traffic-accounting/feed/ 6 ping command: TTL Expired In Transit Error and Solutionhttp://www.cyberciti.biz/faq/ttl-expired-in-transit-linux-unix-windows-router-error/ http://www.cyberciti.biz/faq/ttl-expired-in-transit-linux-unix-windows-router-error/#comments Wed, 27 Oct 2010 10:28:12 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9149 When I try to ping other UNIX / Linux / BSD or MS-Windows servers in our network I get the following message:
TTL Expired In Transit
How do I fix this problem?]]> http://www.cyberciti.biz/faq/ttl-expired-in-transit-linux-unix-windows-router-error/feed/ 1 Replicating Content Between USA, Japan (Asia) and UK (Europe) Webservershttp://www.cyberciti.biz/faq/linux-unix-server-replicating-content-us-europe-asia-webservers/ http://www.cyberciti.biz/faq/linux-unix-server-replicating-content-us-europe-asia-webservers/#comments Tue, 26 Oct 2010 19:47:10 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=9103 We have corporate intranet network for our web site as us.example.com, jp.example.com (asia.example.com), uk.example.com (eu.example.com). How do I replicate static content stored at /var/www/corporate_lan/ such as javascript files, css files, and images between our USA, Japan and UK web servers running under UNIX or CentOS or Redhat Enterprise Linux based Apache servers?]]> http://www.cyberciti.biz/faq/linux-unix-server-replicating-content-us-europe-asia-webservers/feed/ 5 Use wget with Squid Proxy Serverhttp://www.cyberciti.biz/faq/how-do-i-make-wget-work-with-squid/ http://www.cyberciti.biz/faq/how-do-i-make-wget-work-with-squid/#comments Sat, 28 Aug 2010 09:20:56 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8670 How do I make wget work with Squid under UNIX or Linux operating systems?]]> http://www.cyberciti.biz/faq/how-do-i-make-wget-work-with-squid/feed/ 0 Network: Monitor Outgoing Bandwidth Latency / Jitterhttp://www.cyberciti.biz/faq/linux-unix-windows-monitor-outgoing-bandwidth-latency/ http://www.cyberciti.biz/faq/linux-unix-windows-monitor-outgoing-bandwidth-latency/#comments Sun, 22 Aug 2010 11:46:08 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8645 I've servers in two different data centers and connected via leased lines. How do I find out bandwidth latency and jitter between two servers using MS-Windows server, UNIX or Linux operating systems? How do I verify that my leased line based internet connection is stable between two data centers?]]> http://www.cyberciti.biz/faq/linux-unix-windows-monitor-outgoing-bandwidth-latency/feed/ 1 Linux: Setup SSH To Tunnel VNC Traffic Though Internethttp://www.cyberciti.biz/faq/howto-setup-vnc-server-ssh-client-tunnel-via-internet/ http://www.cyberciti.biz/faq/howto-setup-vnc-server-ssh-client-tunnel-via-internet/#comments Fri, 16 Jul 2010 00:39:58 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8383 I have UNIX workstation and Linux server at work and Ubuntu desktop at home. It is recommended that I use ssh tunnel the VNC protocol for secure communication. How do I access my UNIX workstation desktop here at home over the Internet using ssh?]]> http://www.cyberciti.biz/faq/howto-setup-vnc-server-ssh-client-tunnel-via-internet/feed/ 3 Reboot Linksys WAG160N / WAG54 / WAG320 / WAG120N Router / Gatewayhttp://www.cyberciti.biz/faq/reboot-linksys-wag160n-wag54-wag320-wag120n-router-gateway/ http://www.cyberciti.biz/faq/reboot-linksys-wag160n-wag54-wag320-wag120n-router-gateway/#comments Thu, 15 Jul 2010 13:11:29 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8302 I'm using a Cisco Linksys WAG320N Router to connect my OS X UNIX and Linux systems to the Web. How do I reboot my Linksys WAG series router / gateway (modem) from UNIX / Linux / OS X bash command prompt or using a shell script?]]> http://www.cyberciti.biz/faq/reboot-linksys-wag160n-wag54-wag320-wag120n-router-gateway/feed/ 5 Linux: Subnet (CIDR) Calculatorhttp://www.cyberciti.biz/faq/linux-subnet-calculator-cidr/ http://www.cyberciti.biz/faq/linux-subnet-calculator-cidr/#comments Wed, 07 Jul 2010 08:31:15 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8212 I'm new to networking and need help with network settings. I'm looking for a tool for calculating available host address ranges with CIDR using Linux command prompt. How do I use subnet calculator under Linux or UNIX?]]> http://www.cyberciti.biz/faq/linux-subnet-calculator-cidr/feed/ 4 Verify: Keepalived IP Failover Working Or Not With tcpdump Commandhttp://www.cyberciti.biz/faq/linux-unix-verify-keepalived-working-or-not/ http://www.cyberciti.biz/faq/linux-unix-verify-keepalived-working-or-not/#comments Thu, 01 Jul 2010 22:09:24 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=8021 I've installed keepalived IP failover software as described here. But how do I verify it is working or not?]]> http://www.cyberciti.biz/faq/linux-unix-verify-keepalived-working-or-not/feed/ 2 dhcpdump: Monitor DHCP Traffic For Debugging Purposehttp://www.cyberciti.biz/faq/linux-unix-dhcpdump-monitor-dhcp-traffic/ http://www.cyberciti.biz/faq/linux-unix-dhcpdump-monitor-dhcp-traffic/#comments Thu, 06 May 2010 10:20:01 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=7358 How do I dump DHCP packets under Linux / UNIX for monitoring or debugging purpose? ]]> http://www.cyberciti.biz/faq/linux-unix-dhcpdump-monitor-dhcp-traffic/feed/ 1 tcpdump: Monitor ALL eth1 Traffic Except My Own SSH Sessionhttp://www.cyberciti.biz/faq/linux-monitor-all-network-traffic-except-ssh-port-22/ http://www.cyberciti.biz/faq/linux-monitor-all-network-traffic-except-ssh-port-22/#comments Wed, 14 Apr 2010 09:28:53 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=7199 I'm using tcpdump to dump, debug and monitor traffic on a network. However, there is lots of noise and I would like to exclude ssh from my dumps. How do I monitor all traffic except my ssh session?]]> http://www.cyberciti.biz/faq/linux-monitor-all-network-traffic-except-ssh-port-22/feed/ 5 tc: Linux HTTP Outgoing Traffic Shaping (Port 80 Traffic Shaping)http://www.cyberciti.biz/faq/linux-traffic-shaping-using-tc-to-control-http-traffic/ http://www.cyberciti.biz/faq/linux-traffic-shaping-using-tc-to-control-http-traffic/#comments Tue, 13 Apr 2010 13:55:24 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=7139 I've 10Mbps server port dedicated to our small business server. The server also act as a backup DNS server and I'd like to slow down outbound traffic on port 80. How do I limit bandwidth allocation to http service 5Mbps (burst to 8Mbps) at peak times so that DNS and other service will not go down due to heavy activity under Linux operating systems?]]> http://www.cyberciti.biz/faq/linux-traffic-shaping-using-tc-to-control-http-traffic/feed/ 2 HowTo: Verify My NTP Working Or Nothttp://www.cyberciti.biz/faq/linux-unix-bsd-is-ntp-client-working/ http://www.cyberciti.biz/faq/linux-unix-bsd-is-ntp-client-working/#comments Thu, 25 Mar 2010 17:11:28 +0000 Vivek Gite http://www.cyberciti.biz/faq/?p=6885 I've setup an NTP (Network Time Protocol) client and/or server to manage the system clock over a network. But, how do I verify that it is working correctly?]]> http://www.cyberciti.biz/faq/linux-unix-bsd-is-ntp-client-working/feed/ 1