I hope to fidn possible cause of DNS issue, reported by one of our PPPoE client.
he’s got his public IP xx.xxx.162.201, giving by Radius Server when the PPPoE authentication takes place.
all used to work fine until we added 2nd ISP to our network.
Our change:
2nd ISP added, but this particular customer is going through the origianl ISP. We have OSPF and both ISPs are added in the interface.
OSPD create dynamic routing entries which included both ISP’s gateway :
0 ADo 0.0.0.0/0 10.10.0.249 110
10.10.0.241
where 10.10.0.249 is ISP1 and 10.10.0.241 is ISP2
then in Mangle we tell which part of our network goes to which ISP:
some goes to ISP2
add action=route chain=prerouting comment=SubnetA passthrough=no route-dst=10.10.0.241 src-address=10.10.11.0/24
this particular customer goes to ISP1
add action=route chain=prerouting comment=Static passthrough=no route-dst=10.10.0.249 src-address=xx.xxx.162.192/28
It works, 99%. However, it seems that intermittently, his PCs with in the LAN will not able to browse the Intenet:
Google search, no problem, click on any of the search result, nothing happens.
some web URL won’t work either
if you do nslookup from the PCs, you get an IP, if you type the IP into browser, it works
if you put the same URL into the browser, times out
The customer’s router is doing the PPPoE dialing and they have tried USG, Edgerouter and Cisco, all the same.
I’ve changed
/ip dns query server timeout to 4s
set allow-remote-requests=yes query-server-timeout=4s servers=8.8.8.8
not sure if is relevent though because it should not use our router as DNS server
add address=10.10.3.0/24 comment="PPPoE Clients" dns-server=8.8.8.8 gateway=10.10.3.1
and client router can set their own DNS server which is 8.8.8.8 currently.
MTU is set o 1480 for the PPPoE connections and all other customers don’t have problems.
any thought?