Geekzone: technology news, blogs, forums
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.

1200 posts

Uber Geek
+1 received by user: 3


Topic # 11713 7-Feb-2007 19:22
Send private message

Hello Everyone,

I have a client which is having issues very symptoms very similar to MTU packet size issues (unreliable browsing, Terminal Server sessions failing etc)

This client has a laptop and a 3G card, and sits out on a boat way past great barrier island. They can only get GPRS service, but has been working fine for the last year or so.

I setup my laptop to replicate their settings (Clean install of Windows XP) VMC 7.03.0004 (latest) and a 3G Card locked to GPRS with APN of and internet.

Unusual results. I can ping usually with up to a 1500 MTU from a broadband connection (Clear's DNS servers.)

From the GPRS connection I can only send a ping -f -l 64 and get a reply.

If I send a do not fragment and packet size of 65 and above it does not get a reply - BUT ALSO does not recieve a packet needs to be fragmented.

The maxmum packet I can sent with a fragmentation error is 1476, which seems right from what google says (but most dialup connections are 576 MTU)

My gateway when on Vodafone is I can send packets of up to 1476, but they get eaten after this. Seems to be a GPRS problem, and perhaps even only on this gateway.

I called Vodafone Data support, but the only guy which knew had gone home for the day.

Questions - Whats the MTU meant to be for Vodafone GPRS??? Surely it isn't 64!!!

Tyler - Parnell Geek - iPhone 3G - Lenovo X301 - Kaseya - Great Western Steak House, these are some of my favourite things.

Create new topic

1200 posts

Uber Geek
+1 received by user: 3


  Reply # 60040 7-Feb-2007 19:48
Send private message

I dug a little deeper, I did a tracert and then pinged each host, some didn't respond, and the ones that did allowed 1765 sized packets all the way to what looks like the internet gateway then simply dropped them, unless they were 64 bytes or under!

  1   577 ms   695 ms   683 ms [myself]
  2   650 ms   581 ms   580 ms
  3   681 ms   576 ms   581 ms
  4   694 ms   599 ms   599 ms [not pingable]
  5   501 ms   581 ms   737 ms [not pingable]
  6   761 ms   719 ms   839 ms [not pingable]
  7   594 ms   599 ms   737 ms
  8   772 ms   737 ms   719 ms

Tyler - Parnell Geek - iPhone 3G - Lenovo X301 - Kaseya - Great Western Steak House, these are some of my favourite things.

Create new topic

Twitter »

Follow us to receive Twitter updates when new discussions are posted in our forums:

Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:

Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:

News »

N4L helping TAKA Trust bridge the digital divide for Lower Hutt students
Posted 18-Jun-2018 13:08

Winners Announced for 2018 CIO Awards
Posted 18-Jun-2018 13:03

Logitech Rally sets new standard for USB-connected video conference cameras
Posted 18-Jun-2018 09:27

Russell Stanners steps down as Vodafone NZ CEO
Posted 12-Jun-2018 09:13

Intergen recognised as 2018 Microsoft Country Partner of the Year for New Zealand
Posted 12-Jun-2018 08:00

Finalists Announced For Microsoft NZ Partner Awards
Posted 6-Jun-2018 15:12

Vocus Group and Vodafone announce joint venture to accelerate fibre innovation
Posted 5-Jun-2018 10:52 to launch Kogan Mobile in New Zealand
Posted 4-Jun-2018 14:34

Enable doubles fibre broadband speeds for its most popular wholesale service in Christchurch
Posted 2-Jun-2018 20:07

All or Nothing: New Zealand All Blacks arrives on Amazon Prime Video
Posted 2-Jun-2018 16:21

Innovation Grant, High Tech Awards and new USA office for Kiwi tech company SwipedOn
Posted 1-Jun-2018 20:54

Commerce Commission warns Apple for misleading consumers about their rights
Posted 30-May-2018 13:15

IBM leads Call for Code to use cloud, data, AI, blockchain for natural disaster relief
Posted 25-May-2018 14:12

New FUJIFILM X-T100 aims to do better job than smartphones
Posted 24-May-2018 20:17

Stuff takes 100% ownership of Stuff Fibre
Posted 24-May-2018 19:41

Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.

Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.