Slow HTTP downloads through Cisco ASA 5500

Recently we noticed weird behavior downloading files from certain sites. The transfer would start out fast (around 10 MB/s), then after a couple of seconds it would plummet to around 9 KB/s. It didn’t happen for every file or every site: downloads from S3 buckets were still particularly fast. But some files that I remember being particularly fast were now showing this weird fast/slow/fast/slow behavior, for example the Sun JDK and ISOs from rit.edu that used to saturate our pipe were now getting all cRAzY.

After some poking around I decided to test HTTP versus FTP to see if it could be an application/protocol-level issue. The easiest way to do this was to find a file available via both FTP and HTTP and download it via both protocols. This is where mirrors.rit.edu came in handy. I used cURL to download it and noticed that via HTTP it was much slower than over FTP:

[evan@boba 16:07:03 ~]$ curl -O ftp://mirrors.rit.edu/pub/centos/6/isos/x86_64/CentOS-6.2-x86_64-netinstall.iso
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  227M  100  227M    0     0   9.8M      0  0:00:22  0:00:22 --:--:-- 7816k
[evan@boba 16:07:33 ~]$ rm CentOS-6.2-x86_64-netinstall.iso 
[evan@boba 16:07:39 ~]$ curl -O http://mirrors.rit.edu/centos/6/isos/x86_64/CentOS-6.2-x86_64-netinstall.iso
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  227M  100  227M    0     0  5686k      0  0:00:40  0:00:40 --:--:-- 6269k

22 seconds via FTP at 9.8MB/s average, 40 seconds over HTTP at 5.6 MB/s average (which was one of the better HTTP runs).

This was affecting all machines on our network, and had nothing to do with the per-machine iptables rules (verified by flushing all rules). The only thing I could think of that might affect all machines, but only HTTP and not FTP would be something like packet inspection. Well, turns out that http packet inspection is on by default on the ASA. So I disabled it as described here:

Zeus(config)# conf t
Zeus(config)# policy-map global_policy
Zeus(config-pmap)# class inspection_default
Zeus(config-pmap-c)# no inspect http
Zeus(config-pmap-c)# write mem
Building configuration...

Since then HTTP transfers have been consistently fast.

Macbook Pro locks up with SSD installed.

A few weeks ago I switched from my trusty old HP nc8430 to a Macbook Pro (MC118LL/A) that was left spare when another employee left. I mostly enjoyed using Linux but I was tired of dealing with weird quirks like having X lock up, essentially forcing me to do a hard reboot.

To transition, I copied my documents from Linux to Mac, then turned off the Linux laptop. Surprisingly I found I didn’t need to turn Linux back on at all.
Continue reading “Macbook Pro locks up with SSD installed.”

FCC Report shows Verizon much faster than Cablevision

The FCC recently conducted a study of some of the top broadband ISPs in the country and measured customers’ actual bandwidth as compared to what the ISPs advertised. FiOS really came out on top.

The report is available on the FCC site. The bottom line, though, is that Verizon FiOS averaged nearly 120% of advertised speed (i.e., more than was advertised) and Cablevision was between 50% and 75% of advertised speeds. Latency (ping) was also heavily in FiOS’s favor.

FCC - Fios vs Cablevision
FCC - Fios vs Cablevision

Continue reading “FCC Report shows Verizon much faster than Cablevision”

TP-Link TL-WR841ND v7 802.11n router, wireless dies after a few days

I mentioned in a previous post that I got the TP-Link TL-WR841ND 802.11n wifi router and it solved the speed problems I was noticing with wifi connections since going from FiOS to Cablevision. This seems to be the case still, however I’ve now had another problem with the TP router. Basically, wireless becomes unusable and the web UI becomes inaccessible. The SSID still shows up but I can’t get an IP address. When accessing it from the wired LAN via a browser, the connection times out – apparently whatever’s going on inside the router is also crashing its internal webserver.

Power-cycling the router resolved the issue both times it occurred (most recently tonight), but twice is two times too many. Tonight I downloaded and installed DD-WRT v24-sp2 and configured it. It only took a few minutes – I was pretty impressed with dd-wrt – though I was surprised not to see SNMP monitoring included. Not sure if I missed it in the UI but I assumed it would be under “Services,” and I didn’t see it there. I tried snmpwalk against the router and it returned nothing, so it’s not on by default.

Anyway, hopefully dd-wrt will give me better luck than the native TP-Link firmware. It seems to be a good router hardware wise, but crashing every few days negates that.

Update: April 19, 2011: I’ve had DD-WRT running for a few weeks now on the TP-Link router and it’s been great. No reboots required. For some reason DD-WRT doesn’t seem to have SNMP available, at least not through the web UI, but other than that it’s far better than the default TP-Link software.

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Speed comparison: Optimum Boost vs Verizon FiOS

Optimum Boost advertises 30 Mbps down, 5 Mbps up. Here’s a speed test I just ran at Ookla’s SpeedTest.net:

(My desktop is plugged into the router, the router is plugged into the Arris cablemodem.)

Here’s one of the last speed tests I did with Verizon, on 2/15. I had the 25/15 internet package:

(Desktop was plugged into 8-port Linksys 100 Mbit switch, the switch was plugged into the FiOS/ActionTec router.)

Continue reading “Speed comparison: Optimum Boost vs Verizon FiOS”

FiOS speed 10 months later, better than ever.

I switched to FiOS in December, 2009, and I was pretty apprehensive, having been a Cablevision customer for many years. I really had no problem with Cablevision’s service, I just thought their pricing was much too high in the face of the new competition (and deals) Verizon was offering. I ended up going with Verizon due to their awesome deal, but now it’s almost a year later and I can’t imagine going back to Optimum. It’ll probably come down to price when the current promo pricing I have with Verizon ends, but if the price was equal then no contest – I’d stick with FiOS.