Web server and domain diagnosis

I don’t know how many times I’ve been asked to quote on doing web development when a client has no idea of who is hosting the current site or what kind of technology is on the server. So this may come in handy for those situations where you don’t have the time to wait for your client’s IT department to call you back…

To find out where the site is hosted:

1. Query the TLD whois. For co.za sites it’s http://whois.co.za. For .com it’s http://www.internic.net/whois.html. This will get you the nameserver and person who registered the site, not necessarily the host.
2. To get the host, go to a command prompt / shell and type ping www.domainname.com. You will get an IP address. You can use the nslookup command to get the name of the server, which will invariably give you the host name: nslookup <ipaddress>.

Checking whether DNS records have been updated:

I’ve also been in the situation where client has requested a domain be moved to a different server or has signed up for a new hosting account and the domain hasn’t propagated. Hosts generally say that domain transfer and propagation can take a couple of days for the cache to clear. The problem is that if they have messed up the DNS or haven’t bothered to update zone files, you can site there for a week and hope that the propagation is still happening without knowing. Enter dig. There’s a online version at mice and men which helps you look at the DNS records directly to see if they have been updated yet.

1. Go to the online dig tool at: http://dig.menandmice.com/knowledgehub/tools/dig. You can use the bash dig command in linux – I just find this easier.
2. Type in the nameserver from the whois records above and the name of the domain.
3. The answer section in the returned dig results will give you the ip address from the authoritative name server which the rest of the world is talking to.
4. This is more reliable than ping as it queries the nameserver directly, whereas ping will return an IP address which could come from a DNS cache.
5. It is more than likely that the domain should be transferred within two days of the changes to the DNS records.
6. The dig tool also allows you to view other records e.g. mail server and subdomains.

Checking server software and platform

1. You’ll need to view response headers from a http request – the server will return “Server” response header. Some servers will give you more information, some will give you less.
2. You can use the Firefox developer tools plugin to view the headers: webdeveloper toolbar > Information > View response headers (at the bottom)
3. The response will tell you what operating system, server software, software version and software plugins the server is running.
4. There are online tools which can do this (notably http://www.dotcomunderground.com/web-tools/ ), but I have had some issues with headers returned as arrays.