I will do a seperate blog post reviewing Ubuntu 11.04 specially the new Unity interface, but for now I am trying to help Linux community by additonal mirror.

Incase you are going to download Ubuntu – I would encourage you to use this mirror for Asian and European region.

http://server7.anuragbhatia.com/Ubuntu/11.04/release/

Update: Mirror has been removed as of now. 

Keep spreading the Linux!

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.

So at this point a good question can be – where does the chain start?

Email hosting consists of 3 parts:

1. Domain Registry record
2. DNS Hosting
3. Email Hosting

Domain Registry record:

Start by checking the domain registration. You can do that using any whois service like who.is, drwhois.com etc. Make sure your domain isn’t expired. If it is, quickly visit your domain registrar control panel and renew it. Most smtp servers keep re-trying to deliver email for around 48hours, so if your domain is expired, you should renew it quickly so that future attempts at delivery will work correctly.

DNS Hosting:

If domain registry is OK, then proceed with checking things at DNS hosting.

DNS servers play an important role in email delivery by giving your MX record to sender’s server which is like an “address” of email host. So you can try sending a DNS query to dns servers for MX records.

You can use online nslookup tools like Zoneedit’s nslookup or network tools nslookup or if you want to try to lookup from your system, use “nslookup” command in Windows DOS (as shown here) and “dig” in Linux (shown here). If server doesn’t returns MX records, then try looking up for “SOA” on that server for your domain. You will probably find no SOA records which “technically” means that server isn’t hosting dns records for your domain. In real world it can be billing issues with host or accidential removal of domain. If you don’t see any SOA records, immediately contact web host via phone. If you are using any decent web host, you can expect things to be up within a couple of minutes. Otherwise I would recommend using any free dns host like editdns or zoneedit. Just signup for a free account with them, add your domain, and then DNS records (MX and A records) followed by change in name servers of your domain.

Email Hosting:

If your DNS server is returning MX records, you can proceed to the next part of chain – email hosting. If your MX records are OK and you are still not getting emails, your of email is likely bouncing and the bounced email will include the “cause” of the bounce back. It can be email account doesn’t exist or server is not accepting email. In most such cases, you would have to contact your email host for help and it can take a day or so to sort out the issue. The best thing you can do in such time is set up a temporary redirection – based email host to prevent bounce back.

You can use free email forwarders like zonedit or editdns to get all incoming emails forwarded to your personal gmail/yahoo account.

To setup forwarding – signup for a free account with provider, add your domain and setup email forwarding for all incoming emails.Then query the dns server of that host for MX records of your domain and set those MX records at existing dns hosting (to prevent hassle of shifting dns hosting).

Summary:

Happy hosting!

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?

Nice one!

He is right on fact that aspmx.googlemail.com does NOT resolve. Ok why?

anurag@root]$ dig aspmx.googlemail.com a

; <<>> DiG 9.3.4-P1.1 <<>> aspmx.googlemail.com a
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42050
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;aspmx.googlemail.com.          IN      A

;; Query time: 100 msec
;; SERVER: 66.33.216.208#53(66.33.216.208)
;; WHEN: Wed Aug  5 02:48:00 2009
;; MSG SIZE  rcvd: 38

[anurag@root]$

Thus no A record which means it won’t resolve, BUT one must remember that a zone can have many records working side by side offering their own feature, like – MX records can be there with/without A, same with txt records, and few other also.

Now observing the spf record by Google – “v=spf1 include:aspmx.googlemail.com ~all”

here include:aspmx.googlemail.com

means to include the spf record of aspmx.googlemail.com which makes sense as:

[anurag@root]$ dig aspmx.googlemail.com txt

; <<>> DiG 9.3.4-P1.1 <<>> aspmx.googlemail.com txt
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30134
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;aspmx.googlemail.com.          IN      TXT

;; ANSWER SECTION:
aspmx.googlemail.com.   7178    IN      TXT     "v=spf1 redirect=_spf.google.com"

;; Query time: 14 msec
;; SERVER: 66.33.216.208#53(66.33.216.208)
;; WHEN: Wed Aug  5 02:54:02 2009
;; MSG SIZE  rcvd: 82

[anurag@root]$

Now it means spf record for aspmx.googlemail.com is “v=spf1 redirect=_spf.google.com”

Now trying to understand _spf.google.com

underscore right in start makes it different from a sub-zone since it can’t be used as a domain but will still remain a working sub zone in terms of DNS.

So now since it can’t be used as a  sub domain i.e which can be used to be attached with web server and can supply pages via ftp, there is no meaning of A record for it here.

Checking txt string of _spf.google.com

[anurag@root]$ dig _spf.google.com txt

; <<>> DiG 9.3.4-P1.1 <<>> _spf.google.com txt
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52983
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;_spf.google.com.               IN      TXT

;; ANSWER SECTION:
_spf.google.com.        300     IN      TXT     "v=spf1 ip4:216.239.32.0/19 ip4:64.233.160.0/19 ip4:66.249.80.0/20 ip4:72.14.192.0/18 ip4:209.85.128.0/17 ip4:66.102.0.0/20 ip4:74.125.0.0/16 ip4:64.18.0.0/20 ip4:207.126.144.0/20 ?all"

;; Query time: 29 msec
;; SERVER: 66.33.216.208#53(66.33.216.208)
;; WHEN: Wed Aug  5 02:57:26 2009
;; MSG SIZE  rcvd: 229

[anurag@root]$

And here we got it!

So much information in just one hostname!

“v=spf1 ip4:216.239.32.0/19 ip4:64.233.160.0/19 ip4:66.249.80.0/20 ip4:72.14.192.0/18 ip4:209.85.128.0/17 ip4:66.102.0.0/20 ip4:74.125.0.0/16 ip4:64.18.0.0/20 ip4:207.126.144.0/20 ?all” is a part of SPF record which Google makes its Google Apps users to use.

Thus using

“v=spf1 include:aspmx.googlemail.com ~all” in spf tells that “this domain allows all of the server on this ip range – ip4:216.239.32.0/19 ip4:64.233.160.0/19 ip4:66.249.80.0/20 ip4:72.14.192.0/18 ip4:209.85.128.0/17 ip4:66.102.0.0/20 ip4:74.125.0.0/16 ip4:64.18.0.0/20 ip4:207.126.144.0/20 as authorized to send email on behalf of that domain.

So that’s how spf works in this case.

[ratings]

SO lets see the possible ways out to the issue:

1. use redirection offered by Registrar (eNom, Godaddy, name.com etc…)
2. use redirection offered by third party dns hosts. (only redirection and NOT dns hosting)

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:

1. Everydns
2. Editdns
3. Zoneedit

here i like #1 the most as for redirection as its really fast and simple (though as dns host it is worst!)

and so i will be giving steps for setting up redirection only in everydns…..and anyone can easily use any other service….as steps will be quite similar…

Everydns

To use its redirection, follow these steps:

1. Get a free account at http://everydns.com
2. now login and then add you domain as webhop….
   i.e you need to add  your-domain.com webhop to http://www.your-domain.com(look at pic. below)
   

   adding domain in everydns

   

3. Now wait for 10-15mins…..
   (so that a zone file is created for your domain on everydns)
4. Now you need to get the ip of everydns redirection server……..which is running redirection script and will be doing redirection of your domain.
   This can be done easily by doing an “A record” lookup for your domain on everydns nameservers…..

   you can either simply use any dns lookup tool like e.g http://zoneedit.com/nslookup.htm here just
   put your domain in first field, select record type – a in second fiend and put ns of everydns to which you want to query….so you can use ns1.everydns.net in 3rd

5. so from here we get ip of server is – 64.158.219.5plz not if you get error like – no a records were found for domain.com on server ns1.everydns.net

   Its just means that everydns server’s are ot hosting your domain yet…wait sometime to see that….

   Incase you are on linux, just put up dig command with “a” and “@” parameters…..
   so the command here as per this example will be

   dig domain.com a @ns1.everydns.net

   [anurag@root ~]$ dig domain.com a @ns1.everydns.net

   ; <<>> DiG 9.3.4-P1 <<>> domain.com a @ns1.everydns.net
   ; (1 server found)
   ;; global options:  printcmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 21777
   ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 4

   ;; QUESTION SECTION:
   ;domain.com.                    IN      A

   ;; ANSWER SECTION:
   domain.com.             3600    IN      A       64.158.219.5

   ;; AUTHORITY SECTION:
   domain.com.             86400   IN      NS      ns1.everydns.net.
   domain.com.             86400   IN      NS      ns2.everydns.net.
   domain.com.             86400   IN      NS      ns3.everydns.net.
   domain.com.             86400   IN      NS      ns4.everydns.net.

   ;; ADDITIONAL SECTION:
   ns1.everydns.net.       7200    IN      A       71.6.202.220
   ns2.everydns.net.       7200    IN      A       204.152.184.150
   ns3.everydns.net.       7200    IN      A       208.76.56.56
   ns4.everydns.net.       7200    IN      A       208.96.6.134

   ;; Query time: 35 msec
   ;; SERVER: 71.6.202.220#53(71.6.202.220)
   ;; WHEN: Sat Nov 29 01:08:52 2008
   ;; MSG SIZE  rcvd: 192

   [anurag@root ~]$

6. now just delete all A records present at your dns hosting for “domain.com”
7. create new A record for domain.com (or root zone…or whatever your dns host calls it) pointing to 64.158.219.5

Hope that will help you in redirection setup

This is one of the common question, people ask me – How to choose a web host?

So now I am posting about choosing a right web host for small biz and mid scale business sites.

Unless you are about to use a really complicated script, there is no need to worry about versions of php and MySQL and other complex factors….

Selection criteria will be based on:

• Web Space & Bandwidth
• Reliability
• Support
• Type of access
• Cost factor
• Account limits

So here we go!

Web Space

Web space is NOT much big issue, but I still see people worrying about those.

Let’s see how:

an average page of a site these days weighs around 300KB (having little flash work and rest data and a few pics.) thus if we take average site up to 8 pages (common for a business site.) thus whole site data is about300 X 8 = 2400KB = 2.4MB

Now adding space for PDF Boucher’s, a few more heavy pages like company’s pics. and other product detailed reports; a few video’s etc…..all will hardly cross 50MB

let’s keep a little reserve scripts – 500MB will more then enough for blog, forum, and other similar scripts

Thus saying 1GB space is TOO much for a corporate site!

I just want to make a point to ignore “web space” factor unless space is less then 1GB, rest just consider other important factors

Then comes bandwidth, now that relies on visitors…lets try to calculate it also

average homepage size – 300KB and contact us page size – 100KB, average product detail pages – 500KB so we can assume here that 90% of visitors will go only through these pages

so 90% visitors will be using – 300+100+500×4 = 2.4MB of bandwidth….so now one can calculate based on that.

so 25GB bandwidth means 10,000+ visits which means 300+ visits a day…just for an average site

so here I just recommend considering your visitors and going with appropriate bandwidth and as for an average site, I personally feel 25GB is more then enough

Reliability

This is an important concept which most of people miss out.

Reliability includes (but now limited to):

• Type of Web Hosting company
  There can be lot of difference if you choose a reseller as your web host, sorry to say BUT mostly they have poor quality of everything (including support, servers, policies) and thus I do NOT recommend going with a reseller unless that is highly popular.
  Now e.g. as per this Hostgator, Dream Host etc are good BUT still host like Go daddy aren’t up to that level.
  So I just want to say preferably go with a Hosting “company” like thing rather then a “reseller”
  And ALWAYS make sure you are owner of domain. NEVER ever register your domain with a hosting company which doesn’t gives you access to domain control panel or doesn’t allow you to switch registrar. That’s the most common way in which people are trapped up!

• Type of Hosting infrastructure. Again an important factor. It includes what type of setup your site is on….that might be a “single” server of a reseller OR a cluster of servers by a company like Dream Host.
  While the 1st one is HIGHLY unsecured (anytime your cPanel account could be hacked) and will suck out your hours to restore back your site.

• Backups – find out if web host is giving free full backups or not. It is one of most important yet most ignored feature.

Check out for frequency of backups, checkout for cost of restoration of backups (it should be free or VERY low cost…) and also ask for time a host needs to restore backup.

Support

This is the thing which you will find in most of articles on choosing a web host. Yea that’s true it’s important. Just consider the following things in support:

• Should be quick (if replies after 24hrs, its almost useless)
• Replies should me sensible.
• Do not give much weightage to chat support, as instant solution to hosting queries is generally not possible. A 24/7/365 email support is good enough.
• And as already stated MOST of “resellers” have poor support.

An interesting question here could be how to know (without purchasing!) a web host about its support!

So the best way out is…contact support with pre-sales queries about various things I had discussed here. If you get reply in 24hrs then it “could be” a good host but if it’s more then 24hrs then it “is” worst host!

Type of access:

It is important to know what type of access your web host will be giving to you. Check out with your host about:

• Type of control panel (cPanel is best recommended for Linux but still control panels which hosts like dream host offer are also fine..)
• Ask about Shell access (you might require them for some script work, etc)

Cost Factor:

Again one of fundamental most factors, here important is MOST of web host don’t give what you want. Let’s take example of Hostagator baby plan; I like it because of great speed servers, good support, no stupid limits. But can ANYONE from Hostgator could explain us which small business site need hundred GB’s of space, TB’s of bandwidth could be an exceptional case for some business BUT 600GB web space, does it makes ANY since when file hosting is not allowed, and you even can’t have more then one backup of your own cPanel account.

• So it means you are paying $8-$9 per month for many resources which you will never use, so just keep that in mind. Don’t pay for 300GB when you need 1GB
• Never have longtime contracts, 1year hosting contract is good enough, and do NOT think about those 5year stuff! yuk!
• Make sure about things like domain transfer fees, cPanel account transfer fees, account restoration fees, etc

Account Limits:

There are some “heavily frustrating” things which just cause web host huge loss of customers and customers to just ignore that host.

Make sure about the following limits:

• no. of sub-domains (must be unlimited or at least 50+)
• no. of add-on and parked domains (must be 20+)
• no. of MySQL databases – SHOULD be UNLIMITED!!!
• no. of FTP accounts – should be unlimited
• no. of auto responders, mailing lists etc in cPanel – should be unlimited
• How much CPU resources you can use (including memory, processor load) and for how long? Typically it is 25% allowed maximum for 90 seconds. (if you have extensive scripting work, you must check it up with host)

I hope you will find this helpful

[ratings]

This is regarding use of “External DNS Host…”

Most of newbies get confused because of type of setup they want…..

Type of DNS setups of site :

1. Web host and dns host both are same…….i.e using web hosts name servers.
2. Using separate DNS host and Web Host…

Both setups have their own advantages and dis-advantages…..like

Setup 1

Here we just use all services of web host including DNS hosting too….

like putting nameservers of Web Hosts @ registrar wrks that way…

This setup can be recommended ONLY when the web host is highly reliable and NOT with free or cheap web hosts. The main reason for that being since most of people now-a-days use email at their domain, and using a cheap or free web host’s dns can cause a whole lot trouble

But its always good type of setup when one is having a really good web host having really high (99.9%+) uptime, and one doesn’t needs access to DNS records of domain (which is often not required by a general user hosting one zone with one host!)

Setup 2

This can be a much much reliable setup, i.e having separate dns hosting other then using web hosts servers for dns hosting.

It can be useful as incase web host goes down, one can still have email working (as mostly people have email servers different from web hosting server!)

And also there is an very interesting fact that Free DNS hosts are HIGHLY reliable as comapred to cheap/free web hosts!!!

Thats my personal experience!

So in this setup easy way is just to create the following basic records

1. A record for root zone pointing to the ip of the web server of your web host.
2. Wildcarded A record (*.domain.com) also pointing to the ip of the web server of your web host (for sub-domains to work…)
3. mx records (incase you are using 3rd party email hosting rather then your web host…) so just simply create mx records with proper priority values …and done!!!but in case you have email hosting same as your web host’s then just leave step 3 and everything will go fine

So here’s the comparison b/w the both hosting methods…

Summary

So finalizing facts, i can just say you MUST go with a good external DNS host (free or paid…) to get full control on DNS things like – DNS records (A,cname,mx,srv,AAAA,NS,HINFO,PTR) , TTL, control on SOA parameters. All these features can be avoided ONLY if you use a really Good web host and are fully satisfied with its features

Thanks for reading and plz don’t forget to leave comments

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