[FS#3830] OpenVPN Client Using TCP Connection Has MTU or TCPMSS Issue
openwrt-bugs at lists.openwrt.org
Wed May 26 13:47:36 PDT 2021
THIS IS AN AUTOMATED MESSAGE, DO NOT REPLY.
A new Flyspray task has been opened. Details are below.
User who did this - Weikai Zhang (weikai)
Attached to Project - OpenWrt/LEDE Project
Summary - OpenVPN Client Using TCP Connection Has MTU or TCPMSS Issue
Task Type - Bug Report
Category - Base system
Status - Unconfirmed
Assigned To -
Operating System - All
Severity - Medium
Priority - Very Low
Reported Version - openwrt-21.02
Due in Version - Undecided
Due Date - Undecided
Details - OpenVPN Client connects to a TCP based OpenVPN server connects fine. However, the connections to remote network servers connect but can't transfer data. The mangle rule with clamp-mss-to-pmtu won't receive any data. Setting tcpmss to something around 1000 will only receive the first 100 - 200 bytes and hang. It's not working until reduced tcpmss to 59.
iptables -t nat -A postrouting_rule -o tun0 -j MASQUERADE
iptables -t mangle -A POSTROUTING -o tun0 -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 59
#iptables -t mangle -A POSTROUTING -o tun0 -p tcp -m tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu
More information can be found at the following URL:
You are receiving this message because you have requested it from the Flyspray bugtracking system. If you did not expect this message or don't want to receive mails in future, you can change your notification settings at the URL shown above.
More information about the openwrt-bugs