Web based network tools

Monday 25th June 2007

Web based network tools

A couple of times on my blog, I have mentioned a network utilities site that I have been working on. It was briefly mentioned in my IPv6 post and I remember saying something about it earlier, but wasn't getting around to making it live and giving a full intro. It also differs in looks when viewed under different browsers.

So instead of putting it off even more, here it is:

Just creating some of the tools, like the Netmask Calculator, has been a challenge, as well as being informative. Working on something like this really refreshes your memory on how the internals work. I also have to appreciate Python and how fun and powerful it is to code in it. I even implemented an access control mechanism to stop abuse of the service though I hope I don't have to enable it.

These are the tools (or utilities) that I currently have, though will add more later. Most of these have IPv6 support:

The part that I'm really bad at is coming up with a good design. I guess you need to have at least some background in arts as well as a less technical approach to things to create something really beautiful. My sites may validate when it comes to good code, syntax and functionality, but they don't seem to be too appealing to the masses. How do you develop a good aesthetic sense?


On 25th June 2007, at 23:52pm PKT, Fawad Halim said:

I'd be interested to know how the email verify utility works. If it uses SMTP VRFY, there's very little chance that it'll give a reliable response. Postfix, for one, won't verify email addresses by default.

The pages for the individual utilities have the forms in the header, which is _very_ confusing IMHO. The main functionality (the textbox, and submit button) would look better in middle block.

On 26th June 2007, at 12:08pm PKT, Sajjad said:


No, I thought of using VRFY, but it isn't supported by Exim either. I implemented the same technique that Exim uses for sender verification, which is to exchange the "mail from" and "rcpt to" commands and read the response of the last command. Seems to work in most cases.

Thanks for the pointer on the form positioning. A couple of other people said the same thing, but I didn't get around to changing it. Fixed now.

On 26th June 2007, at 18:50pm PKT, Atif said:

Great news. I was wondering which DNS servers that site uses for lookups.

On 26th June 2007, at 21:06pm PKT, Fawad Halim said:

Thanks for the explanation. It'll probably work as well as can be expected.

This technique would return false positives for any email address on our company's domain as we have a Postfix based spam filter (Barracuda) in front of the actual mail server, so mail to arbitrary addresses is accepted, but would bounce from the backend server. Not a very good setup, I know.

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