[[email protected] ~]# for i in $( ls /sys/class/net ); do echo -n $i; ethtool $i | grep Link\ d; done eth0 Link detected: yes eth1 Link detected: yes eth2 Link detected: no eth3 Link detected: no lo Link detected: yes tun0 Link detected: yes usb0 Link detected: yes yes: mean cable connected no: no cable connected
Due to last issues with memcache in Our Server, we need to count bandwidth consumed by local memcached instances (alice one for now).
This can be done by adding needed rules to iptables:
iptables -I INPUT -p tcp -s 127.0.0.1 --sport 11211 -j ACCEPT
iptables -I OUTPUT -p tcp -d 127.0.0.1 --dport 11211 -j ACCEPT
[[email protected] user]# iptables -I OUTPUT -p tcp -d 127.0.0.1 --dport 11211 -j ACCEPT [[email protected]@web09 epetrenko]# iptables -I INPUT -p tcp -s 127.0.0.1 --sport 11211 -j ACCEPT
Checking - Confirmation
[[email protected] user]# iptables -nvL Chain INPUT (policy ACCEPT 2211 packets, 1074K bytes) pkts bytes target prot opt in out source destination 189 12405 ACCEPT tcp – 127.0.0.1 0.0.0.0/0 tcp spt:11211 Chain FORWARD (policy ACCEPT 0 packets, 0 bytes) pkts bytes target prot opt in out source destination Chain OUTPUT (policy ACCEPT 2359 packets, 904K bytes) pkts bytes target prot opt in out source destination 707 485K ACCEPT tcp – 0.0.0.0/0 127.0.0.1 tcp dpt:11211
The fallacies are summarized below:
1. The network is reliable. 2. Latency is zero. 3. Bandwidth is infinite. 4. The network is secure. 5. Topology doesn't change. 6. There is one administrator. 7. Transport cost is zero. 8. The network is homogeneous.
Effects of the fallacies
Ignorance of network latency, and of the packet loss it can cause, induces application- and transport-layer developers to allow unbounded traffic, greatly increasing dropped packets and wasting bandwidth.
Complacency regarding network security results in being blindsided by malicious users and programs that continually adapt to security measures.
Multiple administrators, as with subnets for rival companies, may institute conflicting policies of which senders of network traffic must be aware in order to complete their desired paths.
The “hidden” costs of building and maintaining a network or subnet are non-negligible and must consequently be noted in budgets to avoid vast shortfalls.
Ignorance of bandwidth limits on the part of traffic senders can result in bottlenecks over frequency-multiplexed media.
Here is my “First Post” since i start using Octopress as a new blogging platform. Wordpress has been used for my first Blog and it was great but Octopress make me impressive as it is a blogging platform which work good on terminal and different with others.
I have used Wordpress for a long time to take note and share my working experiences (also give an idea to discuss with my friend and my colleagues) for a long time but now i decide to use Octopress instead. It is awesome and a good idea so far.
Besides, i would like to dig deeper into Ruby world which puppet written on. Working as a system engineer and i use puppet to do automation tasks so more knowledge in ruby programming will help my career a lot.
Guys, hope you can find out a helpful info on my posts.
And don’t hesitate to ping me if needs to support on something. My door is always opened :)