I can see heavy confusion on what is 4G? So thought to make a blog post about it.
Some people even feel like….
:) Let’s try to understand from basic definition about 4G.
As per ITU - 4G refers to wireless technologies which gives as fast as 1Gbps speeds when one is stationary, while 100Mbps speeds when one is on move. That’s it. Full stop.
Well, that’s “just in defination”. In real - there is no technology which is real 4G.
Which DNS resolver is better - ISP’s (default) DNS resolver, or Google Public DNS or the pioneer of DNS openDNS or even a local DNS server?
Let’s try to find out! I am sitting on a BSNL data link, and I will try to perform few tests to find that out: Available DNS resolvers to me:
--- 218.248.255.194 ping statistics ---
5 packets transmitted, 4 received, 20% packet loss, time 4001ms
rtt min/avg/max/mdev = 26.978/27.754/29.122/0.897 ms
--- 218.248.255.194 ping statistics ---
5 packets transmitted, 4 received, 20% packet loss, time 4001ms
rtt min/avg/max/mdev = 26.978/**27.754**/29.122/0.897 ms
--- 8.8.8.8 ping statistics --- 5 packets transmitted,
5 received, 0% packet loss,
time 4001ms rtt min/avg/max/mdev = 121.147/121.878/122.951/0.783 ms
--- 208.67.222.222 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4005ms
rtt min/avg/max/mdev = 217.678/**219.528**/222.034/1.717 ms
Next, localhost? :)
Recently lucky mobile users in Haryana got MNP i.e Mobile Number Portability.
I too ported my number out from Airtel to Tata Docomo. Reason remains the super slow GPRS network (yup gprs, not even upgraded to EDGE in most of Haryana) and crazy service activation followed by irritating sms’es.
It took around 20 days in porting of my number, and technically speaking - process is yet not (hundred percent) completed even after a month! One of the problems with system is that whenever one requests for a porting code, it is valid for 15days. If we request for porting code again (via sms) we get same code, with same validity. In my case, I request for code, but I submitted documents for porting after 13days of my initial request. On the day of submission, I requested for code again, and got same code which was expiring after 2days. I did informed retailer about it, but he had no clue. Eventually I submitted form. Next, documents reached company by 16th (or to the middle guy), and they triggered request for porting on 16th day with same old code. Result: Port out request failed, because porting code was expired! It took me over a week to realize that, and eventually I submitted documents again. I submitted documents on Monday, and on a fine thursday evening I realized that I didn’t got any call or sms that day! Later, I found I was even not able to send any sms. Outgoing calls were going fine via Airtel connection. I got clue, and tried using Tata Docomo sim card, and it worked! All was OK other then fact that I was not able to recieve calls from Airtel users on Tata’s sim. Callers were getting message - “The Airtel number you have dialed is switched off!” At this point of time I realized a big problem - due to some bugs in system, new carrier actually accepted my number, while Airtel has yet not ported out my number. Good was that I started getting calls even from Airtel users within a day. Logically speaking all was going OK, other then fact that my Airtel connection still works for outgoing, and even at the time of blogging (after a month of porting) it’s still up! Tata Docomo customer support has no clue about it while Airtel support always requests me to visit Airtel relationship center to get this fixed. (Why really? Can’t they do this ONLINE?!)
So, finally 3G is set to launch in India from Private operators. One of my friend came to me and asked:
Very nice one!
It’s quite strange to see, how users are taking 3G. Actually it has been largely “overestimated” technology, specially from Indian media. Let’s first try to understand - What exactly is 3G? Without going into geeky definitions - 3G is simply upgrade from 2G. It uses higher frequency, and thus has more spectrum available for more bandwidth. That’s all. One important thing we need to understand is - 3G is more or less just a last mile technology i.e it connects telecom network’s exchange to consumer’s device. Mostly 3G, 2G, landline network, and broadband network - all share same core network backhaul. Western countries who did deployed 3G many years back are going into hybrid path of taking 3G to 4G apart form offloading peak data to (wired) broadband networks. They are promoting use of wifi, bringing new gadget FemtoCell. At this time, it doesn’t makes sense to say - 3G is everything! Latest capping on uncapped 3G plans by AT&T is a good example of that.
This is a question that I have been asked many times via email and sometimes even phone! Situation is this: you wake up in the morning and found your email hosting is down. You are not getting any emails, either they are bouncing back or going to a blackhole. What should you do in such a situation? Email service is much like a chain – if any part is broken, you won’t get things working (apart from lots of frustration!). Since it’s like chain, one must follow step by step to find the problem.
Few days back I visited Official Google Apps forum (one of my favorite places) and answered many questions. It was quite after some time i was there and found few cases/questions/problems as really interesting. Here’s one of the questions asked there by a admin named aol985 about SPF records.
His question:
As described in http://www.google.com/support/a/bin/answer.py?hl=en&answer=33786 , I set SPF record for mashfilm.ru domain to “v=spf1 include:aspmx.googlemail.com ~all”. But aspmx.googlemail.com currently does not resolves. Is it correct?
After recieving lots of emails regarding SRV records issue in Google Apps I must say that Google has missing info in their documentation about SRV records. As per refering to official Google’s help here.
It has missing info. about the location servers. Here are those missing SRV records…
client._tcp.YOURDOMAIN.TLD. IN SRV 5 0 5222 talk.l.google.com.
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk1.l.google.com.
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk2.l.google.com.
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk3.l.google.com.
_xmpp-client._tcp.YOURDOMAIN.TLD. IN SRV 20 0 5222 talk4.l.google.com.
So finally saying…..just forget everything and have these SRV records to get your domain’s Gtalk working from external IM services. Feel free to post for any issues.
I am proudly making this post to inform you all guys that Granular 1.0 Final has been released today!!! :)
Enjoy the power of Linux with our user friendly distro. Download Links on my servers:
All the best and keep Granularing!
Glue records
These are the mosy fundamental DNS record which actually start with the lookup. Let’s understand how to come in basic scenario…… Observe two sites - harisri.in & anuragbhatia.com There’s a basic difference in terms of DNS in both sites. Nameservers of harisri.in are ns1.anuragbhatia.com & ns2.anuragbhatia.com which belongs to a totaly seprate zone, but nameservers for anuragbhatia.com are ns1.anuragbhatia.com, ns2.anuragbhatia.com & so….. i.e domain is having nameservers which are sub zones of domain itself.
Most of people face issue in using Google sites is redirection……i,e www.domain.com works fine (becoz of presence of cname record) BUT domain.com fails here…… SO lets see the possible ways out to the issue:
In this post, i will consider #2 as for #1 instructions are already available (Google for them!) and also i guess most of you people are reading this post because you were unable to do the #1! since we are using free services, they are perfect for blogger, small biz sites (having low traffic…i.e less then 10,000 visitors per day) We can use any of following host for setting redirection: