Odd behavior using pppoe on Fibre

[MrDazana]

I own 2 checkpoints and both are doing this. (1530/1570)

Running R81.10 (996000575) on both

While using the PPPoE for WAN,  Some sites are not coming up and some applications are timing out when trying to connect. This is not happening if I switch WAN to DHCP and use the ISP modem as a router. Can't see anything in the logs

I tried setting the MTU to 1492. Done a factory reset on both devices, factory reset on the ISP modem. If I  use the built in PPPoE windows adapter from a laptop, I do not have this issue  so everything is pointing to the check point firewall. 

 Thoughts ?

[Chris_Atkinson · Accepted solution]

Potentially you will need to enable MSS clamping per sk121114.

[MrDazana]

Do you have a direct link to that? can't find anything using the search box above. 

thanks

[PhoneBoy · Accepted solution]

https://support.checkpoint.com/results/sk/sk121114

[MrDazana]

This totally fixed it it ! thanks 

[Chris_Atkinson]

Note: The search box above is limited to the community and not the knowledge base / support center.

[MrDazana]

I did select the knowledge base and came back with 0 results. searched for sk121114

[Chris_Atkinson]

Strange it's searchable for me both via Google & supportcenter using that reference.

[MrDazana]

Adding an update to this issue. I reverted back to factory firmware and setting which is  R80.20.15 (992001653) on both my 1530 and 1570. I did not have to enable MSS clamping but I did have to set the MTU to 1492 on the WAN, VLANs & LAN side.

[MrDazanaCom · Accepted solution]

Update 2. My ISP did a firmware update to the modem after chatting about my  issue to tech who works there.  After the update , I didn't have to use the solution above on both SMB firmware but I did have to set the MTU on the PPPoE and LAN network.

Now back on R81.10  Hope this helps others with simular issue