I have a question about the Smartphone USB tethering wiki entry, specifically in the "Connectivity Issues" section, in the line:
Blockquote Another fix is
Network > Firewall > General Settings: On the 'LAN → WAN' rule, turn on Masquerading and MSS Clamping .
I think I understand why MSS Clamping on this rule might have an impact on MTU-related connection issues, but I'm not clear on why the Masquerading setting on this rule could relate or help. Would someone be able to help clarify this?
masquerading aka NAT is default, i.e. all connections from LAN are translated as if they come from WAN address.
Also MSS clamping is default, the essential part is that IF you reduce MTU then MSS clamping is required to fit your packets in that MTU.
If I'm understanding your reply, both masquerading and MSS Clamping are the default, but on a different rule than is mentioned in the wiki. Both masquerading and MSS clamping appear to be the default in Luci on the WAN --> reject zone, but not the LAN --> WAN zone (rule?) as mentioned in the wiki quote above. I'm not quite sure why this setting is recommended in the wiki for problematic cellular ISPs.
I am as confused as you, just dont bother, mssfix checkbox on wan is sufficient to accommodate forced MTU if any - 1280 min ip6, 576 min ip4, MSS will be calculated discounting protocols overhead.
same about masquerade.
I think it is fixed since https://github.com/openwrt/firewall4/commit/698a53354fd280aae097efe08803c0c9a10c14c2 ie get ruleset.uc from v24 if ur affected on v23
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