Tech Archives – Page 2 of 2

Canon Pixma owners: this simple trick can make your printer's feed rollers grab paper again!

(Grab an old sponge - yes, seriously)

I have a Canon Pixma MG5750, a Currys PC World purchase when I needed a cheap multifunction printer fast. Handy at £45 (another set of genuine ink for it costs the same, go figure). I never expected it to be perfect, I assumed it would at least be able to reliably accomplish basic things like print text onto paper.

Unfortunately, one of the fundamental printer requirements - loading its own paper during print jobs - was a little lacking with this unit. Research indicates it's sadly a common issue with this range of Canon printers.

Soon after buying mine, the paper feed (take-up of paper from the tray into the transport mechanism) started to behave irregularly. Soon after that, I ended up having to nudge each sheet of paper in to the printer, it was unable to take in paper itself. Not convenient.

I put up with this for a while but an attempt to print some documents evening pushed me into investigating. The fix, as it turns out, is really simple!

Dear mailserver operators: PLEASE stop using SSLv3!

I look after a few email servers and after implementing much stricter encryption settings at the start of the year, I noticed some emails were never making it to accounts - being rejected at the negotiation stage (where the remote server sending the email agrees an encryption protocol and cipher with the local server).

I was puzzled by this. TLS is hardly new, yet these servers were only ever attempting to use SSLv3 and then failing to 'upgrade' to TLS - not even TLS1.0. Poor show.

This isn't unique either - I periodically run a script which reports the spread of protocols and ciphers of incoming email connections; here's a sample from one server for the last hour...

...The stats don't make for pretty reading:

MaxMind GeoLite v1 databases discontinued - install GeoLite2

I noticed recently that a few web sites are miscategorising my ISP's static IP as being in the wrong country. I knew it was a recent reallocation of a new block and suspected the web sites were using a stale version of a GeoIP database - probably MaxMind's GeoLite v1 offering.

If you see stuff like this while surfing the web, your IP is probably in the same boat:

It's such a stupid problem, but it's all due to lazy server admins or designers

Tiplet: DO NOT USE the # symbol in Oracle Enterprise Communication Broker passwords!

I've been working with Oracle Session Border Controllers and Enterprise Communications Brokers a lot recently, A couple of weeks ago I encountered what I think is a new - and quite serious - bug (it's with Oracle for investigation) regarding how the devices *mis*handle special characters. If you admin ECBs or SBCs and are planning to change their credentials to include non-alphanumeric characters, read this first.

I've been working with Oracle Session Border Controllers and Enterprise Communications Brokers a lot recently, and I encountered what I think is a new bug (it's with Oracle for investigation).

After deploying some new ECB instances, I changed the login and enable passwords, per the Oracle ACLI guide ("secret login" and "secret enable" at the SSH prompt). I used randomly generated strong passwords which included limited special characters -- "#", "%", "?" and "!".

The ECB appliances use two passwords per username - one to log on to the unit, and one to 'enable' (admin mode for configuring them, similar to Cisco's enable mode).

On one appliance, the new password I generated for it was accepted without complaint when typed and retyped at the confirmation prompt. However, attempting to then authenticate a new session using this password resulted in immediate refusal by the appliance. It effectively denied access, with no recovery method. I had to flatten and redeploy the appliance! Continue reading "Tiplet: DO NOT USE the # symbol in Oracle Enterprise Communication Broker passwords!"