I use SNAP 8 to teach a satellite image processing class in my university. For more than one week our lab computers could not update SNAP due to networking problem but SNAP could be updated from my home network just fine.
I suspect that since the university network uses NAT our IP might get black list.
How to solve this issue?
Is there a way to update SNAP without connection to the server?
Hello,
If you are behind a NAT, there is a limit for the maximum number allowed of open connections (at a time) from a single IP address.
More details on the restrictions:
I’ve been there, but didn’t get a T-shirt. Offline installs are a not uncommon use case. SNAP uses Netbeans, which has offline update capabilities. For your lab, you could mirror the updatecenter folders onto a portable drive at home. In workshops for students from developing countries we learned that students had problems installing and maintaining the software at their home labs, so the workshops began to emphasize self-reliance in installing and maintaining the software. Having students install updates manually from your lab’s server might be a useful part of the learning experience, but you may be surprised by the issues that crop up.
Maybe this can help:
For start, you and your students should try to not perform the update all at once, to avoid depassing the maximum number allowed of open connections (at a time) from the same IP.
However, a banned IP is whitelisted after 24 hours, but you mentioned that the problem persists from more than one week:
Meanwhile I have checked your IP (I assume it’s the same one from which you accessed this forum, from Khon Kaen University), and it’s not in the banned IPs list.
Therefore, maybe there are other issues on your network.
A block can be imposed elsewhere (e.g., for “traffic shaping”), or your lab may be using a different NAT’ed port.
@pod486 Can you run mtr on one of the lab computers (linux or Cygwin) to determine where the block is occurring and verify the IP used for the lab?
Thank you all for the replies.
@oana_hogoiu if the IP is not banned then the problem most likely come from our network. I will check with our IT staffs to solve the issue.
@gnwiii I will try to run mtr and find the causes of the problem later.
Right now, from reading your link, I set up a local update server and change SNAP update center URLs to the local server (Thanks SNAP team to allow this configuration). The update seems to be working fine now and it might be better this way since it reduces SNAP server load and our internet usage.
Glad you have updates working. I assume you are populating your lab server with files downloaded on a different network. A local update server makes sense even for student labs with reliable internet access (assuming such things exist – they are outside my experience).