How can I set MSS on AC68U?

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IceTea

Occasional Visitor
I need to set my MSS to a specific value. I know it can be set through iptables, but I also know that I don't know enough to mess with it. Any help will be appreciated.
 

geobernd

Occasional Visitor
MSS is derived from MTU + header size - which depends on protcol (e.g. IPv4 vs IPv6 etc.)
Not sure why you would want to set MSS instead of MTU
More info:
 

IceTea

Occasional Visitor
MSS is derived from MTU + header size - which depends on protcol (e.g. IPv4 vs IPv6 etc.)
Not sure why you would want to set MSS instead of MTU
More info:
My ISP recommended it after I upgraded to a 1gbps line, my speed keeps being capped at 800-900mbps...
 

ColinTaylor

Part of the Furniture
My ISP recommended it after I upgraded to a 1gbps line, my speed keeps being capped at 800-900mbps...
What do they recommend you set it to? It seems unlikely to be the cause. The most you'll ever get out of the RT-AC68U is ~935Mbps, or less if you have enabled things like QoS or AiProtection.
 

IceTea

Occasional Visitor
What do they recommend you set it to? It seems unlikely to be the cause. The most you'll ever get out of the RT-AC68U is ~935Mbps, or less if you have enabled things like QoS or AiProtection.
They wanted me to set it to 1412, and I have nearly nothing enabled except for connmon and Diversion, and I don't think either of those would interfere. I also have IPv6 enabled. Weirdly enough, I actually managed to hit 1.3gbps on fast.com once or twice but had to set the connections to 30 and the test time to 90 seconds. One of the more tech-savvy guys at the ISP says the MSS is a long shot but worth a try, and that I am more likely limited by the cheapo Calix Gigapoint ONT my FNO installed.
 

ColinTaylor

Part of the Furniture
What is your router's WAN connection type set to, PPPoE?
 

IceTea

Occasional Visitor
What is your router's WAN connection type set to, PPPoE?
Yes. I have been informed that there might be some overhead with the PPPoE, but only supposed to be like 50mbps I think. The 200-300mbps seems like it is way too much. It is also definitely not the ISP, as other people I know get like 980ish Mbps with them.
 

ColinTaylor

Part of the Furniture
As I said, the most you will ever get with that router is ~935Mbps.

You can change the MTU and MRU on the WAN > Internet Connection page. I suggest you experiment with different values (keep both values the same though). 1492 should be correct, but I suppose if there was some bizarre double encapsulation going on somewhere you might need to set it to 1452.
 

IceTea

Occasional Visitor
As I said, the most you will ever get with that router is ~935Mbps.

You can change the MTU and MRU on the WAN > Internet Connection page. I suggest you experiment with different values (keep both values the same though). 1492 should be correct, but I suppose if there was some bizarre double encapsulation going on somewhere you might need to set it to 1452.
Actually tried that, but speeds went down... They did just get back to me, and they think my FNO might have capacity issues for my area.

Do you think it would help a bit if I overclock my router, or is it time to bite the bullet and buy a new one, regardless of the capacity issues?
 

ColinTaylor

Part of the Furniture
You can't overclock that model router any more using Merlin's firmware. But it wouldn't make any difference in this case anyway.
 

ColinTaylor

Part of the Furniture
Sorry I don't have enough experience with other routers to be in a position to say that one is better than another.

Have a look at the SNB charts here. Notice how none of the routers exceed about 924 Mbps (because of their gigabit WAN ports).
 

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