Web browsing on client's pc issue

Hi all .

We have a CCR1009 Router in our office and we put it as a pppoe-client for connecting to our ADSL modem . modem had been setup as bridge and everything goes fine .

But ,

Today we do change our internet service provider and they give us a new modem [ TD LTE modem ] . this modem don’t have bridge mode and its already in NAT mode .

So we do these for connecting to the new modem and internet .

1.We do disable the pppoe-client and connect the modem to router .

2.in IP addresses we add an ip address to the port that modem has been connected . [ IP is the same as modem ip range [ 192.168.10.0/24 is the range ]

3.we do disable the modem DHCP because we want Router act as a DHCP server .

4.then we add a route in ip route and put 0.0.0.0/0 to the modem ip .

5.already we create a NAT rule for masquared the 192.168.10.0/24 and internet access .

in this case router and clients has internet but when a client browse websites or even checking mail via outlock app , website load and after some minutes it says can not find server , or email account says can not reach smtp port but after another try it goes fine !

I search over the forum and I found that the mistake is maybe MTU issue , So I double check the MTU in my router and here are my findings :

there are mangle routes for MTU in my router that works fine with ADSL [ old modem ] and the out interface is pppoe-out1 . but in this new modem when I change the out interface to the eth that new modem has been connected , it shows that it is working and counter works but no luck .

So can someone help me on this issue ? is that MTU issue or not ? and is there any changes need for MTU when I don’t config the router as pppoe and only I do NAT for internet access ?

Thanks .

It is likely to be a MTU issue, but it may require some sniffing to be sure.

First follow the suggestion in my automatic signature below, and explain whether the “client PC” is connected directly to your CCR’s LAN or there is some more complex setup.