Issues with connecting to Access tables via Eduroam

[zebrafoot]

I have been running the company database for the last few years. We have a split database with the tables located on a laptop connected to a router in my boss's house, while each user has a front end on their own computer. Connection into to the tables is via a free Hamachi VPN client. As we work in a university environment, we often used Eduroam for our internet connection when we are in the office, although we also use our home WiFI, when we are not in the university.

Recently, my boss has changed his ISP. The database still works satisfactorily when connecting from home, but when using our Eduroam connection, we can connect to Hamachi and "see" the computer with the tables on it, but Access does not work.

It doesn't seem like an issue with Access per se, but rather an issue with Eduroam establishing a proper connection to my boss's new router. I know it's a long shot, but is there anyone on this forum who would be running a similar setup with any insight into my problem?

Pete

 

[GPGeorge]

I have been running the company database for the last few years. We have a split database with the tables located on a laptop connected to a router in my boss's house, while each user has a front end on their own computer. Connection into to the tables is via a free Hamachi VPN client. As we work in a university environment, we often used Eduroam for our internet connection when we are in the office, although we also use our home WiFI, when we are not in the university.

Recently, my boss has changed his ISP. The database still works satisfactorily when connecting from home, but when using our Eduroam connection, we can connect to Hamachi and "see" the computer with the tables on it, but Access does not work.

It doesn't seem like an issue with Access per se, but rather an issue with Eduroam establishing a proper connection to my boss's new router. I know it's a long shot, but is there anyone on this forum who would be running a similar setup with any insight into my problem?

Pete

If the problem is indeed with this "Eduroam" application, perhaps you could provide some details about how it is supposed to work. Is it proprietary to your University? Is it a commercial product? At least a link to give people a chance to learn what it's all about if you can't explain it yourself.

Also, what does it mean to say, "...Access does not work." It won't start? It raises errors? You can see the computer. but not the applications installed on it, including Access?

When describing a problem, context and details are very helpful. Thank you.

 

[zebrafoot]

If the problem is indeed with this "Eduroam" application, perhaps you could provide some details about how it is supposed to work. Is it proprietary to your University? Is it a commercial product? At least a link to give people a chance to learn what it's all about if you can't explain it yourself.

Also, what does it mean to say, "...Access does not work." It won't start? It raises errors? You can see the computer. but not the applications installed on it, including Access?

When describing a problem, context and details are very helpful. Thank you.

Hello,

Yes, ok, apologies.

I don't know enough about Eduroam to supply much detail, but it is an international WiFi internet service within Universities/higher education.

Access will start (the front end is on my laptop), but the first page of the database does not load, so it's not possible to do anything with it.

 

[GPGeorge]

Hello,

Yes, ok, apologies.

I don't know enough about Eduroam to supply much detail, but it is an international WiFi internet service within Universities/higher education.

Access will start (the front end is on my laptop), but the first page of the database does not load, so it's not possible to do anything with it.

Okay, at first, I wondered if that might be some sort of security configuration which relies on the old IP address. And the fact that your Front End appears not to be loading the initial form (pages are in websites, forms are in Access) suggests there could be a problem with the linked tables when using that Eduroam connection.

How does that work, exactly? Are you able to open other applications on the remote laptop via the Eduroam connection? Or is it only this database application which fails?

Try this, please, and tell us what the result is.

Press and hold the control key on the the keyboard while opening your Access FE. This will bypass startup code in the accdb. Then you can open the Navigation Pane and look at the Linked Tables. Try to open one of them by double-clicking on it. What happens?

You may have to relink the tables, using the Linked Table Manager, but that will depend on your knowing the path to use now, assuming it is different.

 

[zebrafoot]

Okay, at first, I wondered if that might be some sort of security configuration which relies on the old IP address. And the fact that your Front End appears not to be loading the initial form (pages are in websites, forms are in Access) suggests there could be a problem with the linked tables when using that Eduroam connection.

How does that work, exactly? Are you able to open other applications on the remote laptop via the Eduroam connection? Or is it only this database application which fails?

Try this, please, and tell us what the result is.

Press and hold the control key on the the keyboard while opening your Access FE. This will bypass startup code in the accdb. Then you can open the Navigation Pane and look at the Linked Tables. Try to open one of them by double-clicking on it. What happens?

You may have to relink the tables, using the Linked Table Manager, but that will depend on your knowing the path to use now, assuming it is different.

Hi George, and thank you.

I will try when I'm next on site - currently I'm working from home, so I'm unable to replicate the issues.

 

[Gasman]

I would be pinging your bosses IP address. Can you connect to the folder just with explorer?
New ISP would mean new router and perhaps some ports/apps are not allowed through the firewall?
Could be Eduroam uses selective ports for security?

 

[GPGeorge]

I would be pinging your bosses IP address. Can you connect to the folder just with explorer?
New ISP would mean new router and perhaps some ports/apps are not allowed through the firewall?
Could be Eduroam uses selective ports for security?

That's the kind of information I was hoping we could get, but Eduroam seems to be a bit of a black box here.

I'm thinking the connection string in the linked tables might reveal something useful. I should have included that in post #4.

 

[zebrafoot]

Thank you, Gasman.

I can open the folder with file explorer

I would be pinging your bosses IP address. Can you connect to the folder just with explorer?
New ISP would mean new router and perhaps some ports/apps are not allowed through the firewall?
Could be Eduroam uses selective ports for security?

I assume you mean I should do this from work (via Eduroam)? I can ping the computer from home without issue and open the folder to view files on his laptop.

 

[Gasman]

Yes, test with Enduroam, though the tests at home would form a baseline and might provide a clue.

 

[The_Doc_Man]

I looked up Eduroam on the web and found a "how does it work" link.

Eduroam uses something called RADIUS (Remote Access Dial In User Service). This differs from the standard LAN protocol LDAP (Lightweight Directory Access Protocol) in some ways, though you CAN establish some LAN connections through RADIUS.

The big difference is that RADIUS is based on UDP (User Datagram Protocol) whereas LAN/LDAP will use TCP (transmission control protocol). I cannot prove that this difference causes the observed problem, but I strongly suspect that Access (which absolutely REQUIRES use of SMB - Server Message Block, a member of the TCP suite of protocols) does not like this protocol environment. This is a tough call considering that I can't get in and take a full survey of the network including protocol checks. It is therefore a GUESS based on incomplete information. If there is an IT staff you can call, you might discuss this with them. However, it is a bit esoteric unless you have a good networks person on staff to analyze it.

I am thinking that, based on the reliance of UDP as their session protocol, Eduroam is more of a web-oriented protocol, which does not work so well with Access. If so, that might be the source of the problem.

The basic rule is that if you can't connect via SMB, you can't connect an Access front end to an Access back end. It MIGHT (stress MIGHT) be possible if you had your back end on an active SQL engine such as MySQL or SQL Server or SQL Lite or something in that family, after which you could switch to ODBC connections. Again I have no certainty in that since I think ODBC is another member of the TCP family of protocols using port 1433 for initial connection to set up a negotiated port. The initial request is UDP but the data exchanges are not, if I recall that correctly. Therefore, you might again run into an unsupported protocol issue which would stop you dead in your tracks.

That diagnosis is the best I can do remotely and therefore I strongly suggest you talk to whoever manages the RADIUS server for information on supported protocols. I could be wrong about this. It could ALSO be that the new router is merely configured incorrectly and thus disallows SMB protocol. Advanced routers can do that. Again, the IT person who manages the router might need to step in to assess whether there are any filters that would block SMB.

 

[zebrafoot]

Thank you for taking the time to look at this, Doc Man. Food for thought. As a first step I will ask the boss to check the server setup and see if that gives us any further idea of what's happening.

 

[Gasman]

I looked up Eduroam on the web and found a "how does it work" link.

Eduroam uses something called RADIUS (Remote Access Dial In User Service). This differs from the standard LAN protocol LDAP (Lightweight Directory Access Protocol) in some ways, though you CAN establish some LAN connections through RADIUS.

The big difference is that RADIUS is based on UDP (User Datagram Protocol) whereas LAN/LDAP will use TCP (transmission control protocol). I cannot prove that this difference causes the observed problem, but I strongly suspect that Access (which absolutely REQUIRES use of SMB - Server Message Block, a member of the TCP suite of protocols) does not like this protocol environment. This is a tough call considering that I can't get in and take a full survey of the network including protocol checks. It is therefore a GUESS based on incomplete information. If there is an IT staff you can call, you might discuss this with them. However, it is a bit esoteric unless you have a good networks person on staff to analyze it.

I am thinking that, based on the reliance of UDP as their session protocol, Eduroam is more of a web-oriented protocol, which does not work so well with Access. If so, that might be the source of the problem.

The basic rule is that if you can't connect via SMB, you can't connect an Access front end to an Access back end. It MIGHT (stress MIGHT) be possible if you had your back end on an active SQL engine such as MySQL or SQL Server or SQL Lite or something in that family, after which you could switch to ODBC connections. Again I have no certainty in that since I think ODBC is another member of the TCP family of protocols using port 1433 for initial connection to set up a negotiated port. The initial request is UDP but the data exchanges are not, if I recall that correctly. Therefore, you might again run into an unsupported protocol issue which would stop you dead in your tracks.

That diagnosis is the best I can do remotely and therefore I strongly suggest you talk to whoever manages the RADIUS server for information on supported protocols. I could be wrong about this. It could ALSO be that the new router is merely configured incorrectly and thus disallows SMB protocol. Advanced routers can do that. Again, the IT person who manages the router might need to step in to assess whether there are any filters that would block SMB.

I would have to say though, that if it was working fine with the old ISP, most of the caveats would not apply?

 

[The_Doc_Man]

I would have to say though, that if it was working fine with the old ISP, most of the caveats would not apply?

Which is why I closed with having someone check the router's allow/deny settings, since routers these days can be made to be VERY selective. I once ran into a router that explicitly disallowed SMTP (to an SMTP server, no less) when the sender was MSACCESS.EXE running CDO. There is almost no limit to the crazy rules you can toss into routers these days. But my original comment would be valid if the new ISP forced a reload and re-imagining of all prior rule sets.

 

[zebrafoot]

Just dropping back in to say that the issue seems to be resolved. The person who assists with our IT stuff has set up an entirely new Hamachi network for us. Apparently the original connection was via Mesh and he has changed it to something else (Gateway?). This appears to work through Eduroam. These are just meaningless words to me, so I can't explain why the connection to our database suddenly went awry, nor why it is now fixed.

I'd like to thank all of you who offered suggestions, for your kind assistance.