Dynamic DNS and transparent proxies

I prefer having my DynDNS account updated by my Linux-based DSL-500T ADSL modem/router (flashed with Russian firmware) since it means the host updates occur every time a PPP session is established. Otherwise, I would have needed an inefficient cron job at my main box.

I haven't needed to access my PC remotely in the past few months, so I just recently noticed that my DynDNS host wasn't getting updated. At first, I thought there was something wrong with the router, but after my previous blog, I noticed that my host's registered IP address was that of (you guessed it, good for you!) Globe's transparent proxy.

It turns out my router's ddns call (hardcoded in the router's firmware-flashed XML) was using automatic IP resolution, i.e. DynDNS used whatever IP address the update command came from.

So, I downloaded the current XML configuration, made it more editable with HTML Tidy (tidy -xml), fixed the command to use -i ppp0 instead of -r, mashed the XML back into a single line with another one of my quick-and-dirty scripts (clutter), and reflashed it into the router. After it rebooted, my DynDNS account was being updated properly again. Phew.

ddns -u myuser:mypass -h myhost.at.dyndns -w -r -q -i ppp0

If any of you are having similar problems, check if your ISP has a transparent proxy. If you're lucky enough to be able to customize the commands your router runs, the above might be of some help.

Of course, if you're really lucky, your router doesn't have this problem in the first place. :-P

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Indiggnant at Globe DSL

I've been getting a blank page trying to login at Digg. It seems that a lot of people are having this problem, likely due to some bad transparent proxying by the ISP.

So I did a tcptraceroute to check if Globelines was using one:

# tcptraceroute digg.com
Selected device eth0, address 192.168.1.250, port 51873 for outgoing packets
Tracing the path to digg.com (64.191.203.30) on TCP port 80 (http), 30 hops max
1  192.168.1.5  3.372 ms  1.052 ms  0.651 ms
2  203.177.x.x  18.164 ms  18.177 ms  18.692 ms
3  222.127.x.x  18.108 ms  18.133 ms  18.378 ms
4  digg.com (64.191.203.30) [open]  18.395 ms  18.258 ms  20.177 ms

Aha! Time for a bypass.

Since I have SSH access to a number of servers, I just set up a SOCKS tunnel,

$ ssh -ND 8888 my-remote-server

then setup my browser to connect to localhost:8888 (SOCKS v5). I tried logging in to Digg... voilà!

Globeline's transparent proxy (apparently Blue Coat) does work for most sites, so I also installed the FoxyProxy Firefox add-on. It allows me to specify which proxy to use with what sites.

If you don't have access to an external SSH server, and are having similar problems, you could probably just use a public proxy server instead.

UPDATE 1: It seems Globelines has turned off its transparent proxy. A tcptraceroute to digg.com now shows 11 hops, following the same path as the normal traceroute. I wonder if this has anything to do with all those cut underwater cables, or it was just that too many people complained.

UPDATE 2: And... it's back again. Get your act together, Globelines!

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Globe DSL up-down-upgrade

I upgraded my Globelines DSL a couple weeks ago, but yesterday(?) it went back to 512Kbps. Wat fa duck happened, a bad DB restore? :-( After three calls (tech->CS->tech), I was told to monitor the connection within the next 24 hours.

A few minutes ago, I tested it again:


Not shabby at all. Happy happy, joy joy!

Para nga lang akong yoyo.

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