Odd blocking issue on outgoing VPN

[Revelstone77]

I am experiencing a very odd issue. When using my company laptop, I have to connect to them using Cisco AnyConnect VPN. Connecting is no problem, but i cant access some of the resources. Some work, and others dont. I moved the laptop and plugged directly into my ATT gateway, bypassing my Asus AC86U router and everything works perfectly. I can access everything. I was experiencing the same issues on my AC87U before upgrading. Router confiig was created new when I installed the 86U. Connect back through my router and I am back to some things work and others dont. Doesnt matter if I connect wired or wireless. I disabled AiProtection and rebooted the router, but no help. I'm not doing anything fancy, that i know of, that could cause an issue. Anybody have any ideas? I can post anything that might be needed.

Thanks

 

[drabisan]

What's the MTU you can reach with and without VPN on?
Do you have a PPoE on Asus?
It's been a while since I used AnyConnect...there was a setting in ASA&Concentrator to deal with packets with Don't Fragment bit set.

 

[Revelstone77]

What's the MTU you can reach with and without VPN on?
Do you have a PPoE on Asus?
It's been a while since I used AnyConnect...there was a setting in ASA&Concentrator to deal with packets with Don't Fragment bit set.

no PPoE
Not sure how to check MTU. in windows it's fixed to 1500 from what i remember. Couldnt change it anyway, those things are locked down by the company. wondering if enabling Jumbo frames might help

 

[drabisan]

Nope. It can't and it won't.
I can't remember how to check MTU in Windows
Try https://kb.netgear.com/19863/Ping-Test-to-determine-Optimal-MTU-Size-on-Router
Assuming 28 bytes ICMP header, you should be able to ping with 1472. But 1473 should fail if your MTU is 1500.

Do the same test towards the vpn gateway.

 

[CaptainSTX]

Nope. It can't and it won't.
I can't remember how to check MTU in Windows
Try https://kb.netgear.com/19863/Ping-Test-to-determine-Optimal-MTU-Size-on-Router
Assuming 28 bytes ICMP header, you should be able to ping with 1472. But 1473 should fail if your MTU is 1500.

Do the same test towards the vpn gateway.

If you want to check what your your MTU is try this site:

www.speedguide.net:8080

 

[drabisan]

That's much easier!
Didn't knew this site, thanks!

 

[Revelstone77]

Nope. It can't and it won't.
I can't remember how to check MTU in Windows
Try https://kb.netgear.com/19863/Ping-Test-to-determine-Optimal-MTU-Size-on-Router
Assuming 28 bytes ICMP header, you should be able to ping with 1472. But 1473 should fail if your MTU is 1500.

Do the same test towards the vpn gateway.

using speedguide.net my MTU is 1500