bbursley Posted March 28, 2017 Posted March 28, 2017 Sorry if this might be something really old. But I just happened to notice that under the LAN section and WAN section of the netduma there's options for setting the MTU for them.i was unaware of this and how I never saw it I don't know. But have since set both of them to 1492 (ppoe). Is there a reason these are in both areas and will making them different cause issues? I'm assuming it would but since I really have never seen this on any router I don't actually know. Usually only WAN has the option for setting the MTU. I have since changed both to 1492 as apposed to leaving wan 1492 and then LAN to auto or something.
BIG__DOG Posted March 28, 2017 Posted March 28, 2017 leave it set to automatic. Don't tamper with the MTU
e38BimmerFN Posted March 28, 2017 Posted March 28, 2017 Ask your ISP what WAN MTU values to use. They will know. Or leave auto if R1 is detecting it right.
bbursley Posted March 28, 2017 Author Posted March 28, 2017 My MTU is suppose to be 1492. That's what I changed it to in the LAN and WAN sections because it asks for it under both of them. I don't really understand why either. But it didn't make sense to me to leave LAN on auto but change WAN to 1492 so I changed both. I'll recheck with ISP but even when I did the MTU check using ping I had used the correct one. I was just wondering what would happen if you used a lower or different MTU on either for example 1500 LAN 1492 wan etc. I'm assuming you'd have packet loss?
e38BimmerFN Posted March 28, 2017 Posted March 28, 2017 IF the pings are good with current setting then go with it. You'll be fine. You can test out Auto and maybe LAN 1500 at some point to see. Then go back what you have now if those don't work. Connections and packets would be effected by wrong MTU values.
faulko Posted March 29, 2017 Posted March 29, 2017 My MTU is suppose to be 1492. That's what I changed it to in the LAN and WAN sections because it asks for it under both of them. I don't really understand why either. But it didn't make sense to me to leave LAN on auto but change WAN to 1492 so I changed both. I'll recheck with ISP but even when I did the MTU check using ping I had used the correct one. I was just wondering what would happen if you used a lower or different MTU on either for example 1500 LAN 1492 wan etc. I'm assuming you'd have packet loss? Not packet loss but pack fragmentation. MTU or maximum transmission units is the max size a packet can be, if your device has bigger mtu then your isp transmits, then it will fragment into 2 smaller packets, repackage and resend, ie ping loss because it takes longer to get your message across. Same with undersized MTU, you isp is requesting 1492, you throwing 1400 at it it will need to fill the packets to 1492 and resend, again ping increase. Thats my understanding of it, happy to be corrected if im wrong, but as mentioned just leave it at auto unless you have larger then expected pings.
bbursley Posted March 29, 2017 Author Posted March 29, 2017 I understand that and I do believe that's probably true. However info not understand the purpose of having two different places for an MTU lol. I feel like wan would be the only place to set MTU and LAN should just follow whatever LAN says (so to speak). I wonder how many people mess this setting up and get lag for no reason because of doing so. But the real question is does the netduma detect all MTU properly? Has anyone actually tested to be sure? Maybe it would work better for cable vs different types of ppoe etc because of variation from ISP to ISP even though most typically have a standard MTU to go by.
XSXS Posted March 29, 2017 Posted March 29, 2017 I have mine set to automatic but when i do enter them i use 1500. I think i read that off of dslreports after running the mtu test via command line
e38BimmerFN Posted March 29, 2017 Posted March 29, 2017 1500 is used for cable ISP services. 1472 thru 1492 is mostly DSL ISP services. I'd use Automatic on the router. The router can handle MTU values on it's own.
fuzzy clam Posted March 29, 2017 Posted March 29, 2017 I understand that and I do believe that's probably true. However info not understand the purpose of having two different places for an MTU lol. I feel like wan would be the only place to set MTU and LAN should just follow whatever LAN says (so to speak). I wonder how many people mess this setting up and get lag for no reason because of doing so. But the real question is does the netduma detect all MTU properly? Has anyone actually tested to be sure? Maybe it would work better for cable vs different types of ppoe etc because of variation from ISP to ISP even though most typically have a standard MTU to go by. Best bet is to find your correct MTU,which you have done and then I would do one of two things... 1-leave it on auto 2- put the numbers in manually But if you lower your MTU to low it will cause fragmentation of your packets as faulko said and that means increased latency thru having to send the packets again to fill the 1492 cup. So people do lower their MTU settings and say it helps with gaming,I've tried about every trick in the book experimenting with different settings MTU,CC etc and for me I couldn't tell a difference, but your milage may vary.
bbursley Posted March 29, 2017 Author Posted March 29, 2017 Best bet is to find your correct MTU,which you have done and then I would do one of two things... 1-leave it on auto 2- put the numbers in manually But if you lower your MTU to low it will cause fragmentation of your packets as faulko said and that means increased latency thru having to send the packets again to fill the 1492 cup. So people do lower their MTU settings and say it helps with gaming,I've tried about every trick in the book experimenting with different settings MTU,CC etc and for me I couldn't tell a difference, but your milage may vary. Yeah I've tried that as well, I think it's just a placebo effect honestly. However having both wan and LAN matching with MTU probably isn't. So that's what I've done just in case. I'm not sure exactly how the router is supposed to know what my actual MTU is. So I just feel safer than sorry by changing it myself lol.
Administrators Netduma Fraser Posted March 30, 2017 Administrators Posted March 30, 2017 Yeah I've tried that as well, I think it's just a placebo effect honestly. However having both wan and LAN matching with MTU probably isn't. So that's what I've done just in case. I'm not sure exactly how the router is supposed to know what my actual MTU is. So I just feel safer than sorry by changing it myself lol. It would detect it coming from your ISP modem/router.
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