I have tried to change the wan MTU config to different values and it still doesnt work. I moved over the ubuntu to ping and test my MTU. Tried the following for google and it worked.
I do the same command but with opnsense.org and it still times out. Im wondering if maybe its not an MTU issue lmao. I do have ipv6 disabled. Could this be the issue ?
Code Select
ping google.com -c 10 -M do -s 1472
PING google.com (142.250.115.101) 1472(1500) bytes of data.
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=1 ttl=106 time=16.5 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=2 ttl=106 time=14.8 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=3 ttl=106 time=17.4 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=4 ttl=106 time=18.7 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=5 ttl=106 time=17.9 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=6 ttl=106 time=15.9 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=7 ttl=106 time=17.4 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=8 ttl=106 time=14.4 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=9 ttl=106 time=17.0 ms
1480 bytes from rq-in-f101.1e100.net (142.250.115.101): icmp_seq=10 ttl=106 time=18.8 ms
--- google.com ping statistics ---
10 packets transmitted, 10 received, 0% packet loss, time 9014ms
rtt min/avg/max/mdev = 14.393/16.873/18.818/1.429 ms
I do the same command but with opnsense.org and it still times out. Im wondering if maybe its not an MTU issue lmao. I do have ipv6 disabled. Could this be the issue ?
Code Select
ping opnsense.org -c 10 -M do -s 1472
PING opnsense.org (178.162.131.118) 1472(1500) bytes of data.
--- opnsense.org ping statistics ---
10 packets transmitted, 0 received, 100% packet loss, time 9197ms
Quote from: meyergru on November 28, 2024, 03:17:38 AM
And there you have it!
As you can see, the problematic sites cannot be accessed by a payload of 1472 bytes corresponding to a MTU of 1500. That is your problem, not DNS.
The maximum physical MTU of the ethernet adapter has to be reduced by 4 bytes for VLANs, plus 8 bytes for PPPoE encapsulation, thus you will either have to reduce your WAN (net) MTU by these amounts. That is, you should reduce your MTU to 1492 or 1488 bytes.
Or you can hope that your ethernet driver (and your ISP) supports even more than 1500 bytes and set larger sizes for the lower layers beneath the logical WAN adapter in order to keep 1500 bytes.
But beware:
1. The OpnSense settings here are somewhat "wrong". If you have a WAN over PPPoE over VLAN, you "should" have to set WAN = 1500, pppoe0 = 1508, ONT = 1512, but in reality it works for me with these MTUs:
WAN: 1508 (this also sets pppoe0, which you cannot set directly, but really results in 1500 on WAN)
ONT (this means the physical ethernet port): 1512 if you have a VLAN for PPPoE, 1508 if not.
2. Set the above values in the web UI and then reboot - they cannot be changed via UI manipulations, because the order of application seems to be wrong that way.
Retry your tests afterwards.
And, as a courtesy to others, please change your thread title as it is obviously not DNS that is your problem. If your problem is fixed, add [SOLVED] to the thread title.