Hi,
I'm experiencing weird RTT on Linux. Some extra latency exists when ping through the sstp tunnel. And this latency becomes fluctuating randomly, from the lowest to thousands, when there are another streams running through the tunnel, eg, if files being download through the sstp even at low speed.
Physical delay between client and server is only 20ms. The high and unstable latency makes it unpractical on use. Could you look into this problem please? My network only allows SSTP, any other types of tunnel are banned so my server relies on it.
Notice that this problem doesn't exists on Windows with the same sstp accounts. Remote SSTP Server bandwidth is over 40Mbps and I'm the only person using it. My Linux has no problem with pulling files directly at high speed (4MB/s
) from the remote server.
I have tried to reboot my Linux several times and it doesn't fix the problem.
system configurations:
Ubuntu 16.04 LTS
sstp-client V1.0.11 (build from sourceforge.net package)
OpenSSL 1.0.2g 1 Mar 2016
Kernel 4.8.0-41-generic
CPU load is very low, under 10%
ppp configurations
remotename sstp-mc
linkname sstp-mc
ipparam sstp-mc
pty "sstpc --ipparam sstp-mc --nolaunchpppd proxy.server.com"
name account
plugin sstp-pppd-plugin.so
sstp-sock /run/sstpc/sstpc-sstp-mc
mtu 1400 # for windows server
lock
#usepeerdns
require-mschap-v2
refuse-mschap
refuse-eap
refuse-pap
refuse-chap
noauth
nobsdcomp
nodeflate
noccp
novjccomp
#debug
persist
holdoff 2
maxfail 0
#defaultroute
noipdefault
Some highlights on some sysctl config:
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_fack = 1
net.ipv4.tcp_low_latency = 1
net.ipv4.tcp_reordering = 3
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_wmem = 4096 16384 16777216
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_sack = 0
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_window_scaling = 1
full sysctl:
net.ipv4.cipso_cache_bucket_size = 10
net.ipv4.cipso_cache_enable = 1
net.ipv4.cipso_rbm_optfmt = 0
net.ipv4.cipso_rbm_strictvalid = 1
net.ipv4.conf.all.accept_local = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.all.arp_accept = 0
net.ipv4.conf.all.arp_announce = 0
net.ipv4.conf.all.arp_filter = 0
net.ipv4.conf.all.arp_ignore = 0
net.ipv4.conf.all.arp_notify = 0
net.ipv4.conf.all.bootp_relay = 0
net.ipv4.conf.all.disable_policy = 0
net.ipv4.conf.all.disable_xfrm = 0
net.ipv4.conf.all.drop_gratuitous_arp = 0
net.ipv4.conf.all.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.all.force_igmp_version = 0
net.ipv4.conf.all.forwarding = 1
net.ipv4.conf.all.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.all.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.all.ignore_routes_with_linkdown = 0
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.all.mc_forwarding = 0
net.ipv4.conf.all.medium_id = 0
net.ipv4.conf.all.promote_secondaries = 0
net.ipv4.conf.all.proxy_arp = 0
net.ipv4.conf.all.proxy_arp_pvlan = 0
net.ipv4.conf.all.route_localnet = 0
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.all.secure_redirects = 1
net.ipv4.conf.all.send_redirects = 1
net.ipv4.conf.all.shared_media = 1
net.ipv4.conf.all.src_valid_mark = 0
net.ipv4.conf.all.tag = 0
net.ipv4.conf.default.accept_local = 0
net.ipv4.conf.default.accept_redirects = 1
net.ipv4.conf.default.accept_source_route = 1
net.ipv4.conf.default.arp_accept = 0
net.ipv4.conf.default.arp_announce = 0
net.ipv4.conf.default.arp_filter = 0
net.ipv4.conf.default.arp_ignore = 0
net.ipv4.conf.default.arp_notify = 0
net.ipv4.conf.default.bootp_relay = 0
net.ipv4.conf.default.disable_policy = 0
net.ipv4.conf.default.disable_xfrm = 0
net.ipv4.conf.default.drop_gratuitous_arp = 0
net.ipv4.conf.default.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.default.force_igmp_version = 0
net.ipv4.conf.default.forwarding = 1
net.ipv4.conf.default.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.default.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.default.ignore_routes_with_linkdown = 0
net.ipv4.conf.default.log_martians = 0
net.ipv4.conf.default.mc_forwarding = 0
net.ipv4.conf.default.medium_id = 0
net.ipv4.conf.default.promote_secondaries = 0
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.conf.default.proxy_arp_pvlan = 0
net.ipv4.conf.default.route_localnet = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.secure_redirects = 1
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.default.shared_media = 1
net.ipv4.conf.default.src_valid_mark = 0
net.ipv4.conf.default.tag = 0
net.ipv4.conf.ens3.accept_local = 0
net.ipv4.conf.ens3.accept_redirects = 1
net.ipv4.conf.ens3.accept_source_route = 1
net.ipv4.conf.ens3.arp_accept = 0
net.ipv4.conf.ens3.arp_announce = 0
net.ipv4.conf.ens3.arp_filter = 0
net.ipv4.conf.ens3.arp_ignore = 0
net.ipv4.conf.ens3.arp_notify = 0
net.ipv4.conf.ens3.bootp_relay = 0
net.ipv4.conf.ens3.disable_policy = 0
net.ipv4.conf.ens3.disable_xfrm = 0
net.ipv4.conf.ens3.drop_gratuitous_arp = 0
net.ipv4.conf.ens3.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.ens3.force_igmp_version = 0
net.ipv4.conf.ens3.forwarding = 1
net.ipv4.conf.ens3.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.ens3.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.ens3.ignore_routes_with_linkdown = 0
net.ipv4.conf.ens3.log_martians = 0
net.ipv4.conf.ens3.mc_forwarding = 0
net.ipv4.conf.ens3.medium_id = 0
net.ipv4.conf.ens3.promote_secondaries = 0
net.ipv4.conf.ens3.proxy_arp = 0
net.ipv4.conf.ens3.proxy_arp_pvlan = 0
net.ipv4.conf.ens3.route_localnet = 0
net.ipv4.conf.ens3.rp_filter = 1
net.ipv4.conf.ens3.secure_redirects = 1
net.ipv4.conf.ens3.send_redirects = 1
net.ipv4.conf.ens3.shared_media = 1
net.ipv4.conf.ens3.src_valid_mark = 0
net.ipv4.conf.ens3.tag = 0
net.ipv4.conf.ens7.accept_local = 0
net.ipv4.conf.ens7.accept_redirects = 1
net.ipv4.conf.ens7.accept_source_route = 1
net.ipv4.conf.ens7.arp_accept = 0
net.ipv4.conf.ens7.arp_announce = 0
net.ipv4.conf.ens7.arp_filter = 0
net.ipv4.conf.ens7.arp_ignore = 0
net.ipv4.conf.ens7.arp_notify = 0
net.ipv4.conf.ens7.bootp_relay = 0
net.ipv4.conf.ens7.disable_policy = 0
net.ipv4.conf.ens7.disable_xfrm = 0
net.ipv4.conf.ens7.drop_gratuitous_arp = 0
net.ipv4.conf.ens7.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.ens7.force_igmp_version = 0
net.ipv4.conf.ens7.forwarding = 1
net.ipv4.conf.ens7.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.ens7.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.ens7.ignore_routes_with_linkdown = 0
net.ipv4.conf.ens7.log_martians = 0
net.ipv4.conf.ens7.mc_forwarding = 0
net.ipv4.conf.ens7.medium_id = 0
net.ipv4.conf.ens7.promote_secondaries = 0
net.ipv4.conf.ens7.proxy_arp = 0
net.ipv4.conf.ens7.proxy_arp_pvlan = 0
net.ipv4.conf.ens7.route_localnet = 0
net.ipv4.conf.ens7.rp_filter = 1
net.ipv4.conf.ens7.secure_redirects = 1
net.ipv4.conf.ens7.send_redirects = 1
net.ipv4.conf.ens7.shared_media = 1
net.ipv4.conf.ens7.src_valid_mark = 0
net.ipv4.conf.ens7.tag = 0
net.ipv4.conf.lo.accept_local = 0
net.ipv4.conf.lo.accept_redirects = 1
net.ipv4.conf.lo.accept_source_route = 1
net.ipv4.conf.lo.arp_accept = 0
net.ipv4.conf.lo.arp_announce = 0
net.ipv4.conf.lo.arp_filter = 0
net.ipv4.conf.lo.arp_ignore = 0
net.ipv4.conf.lo.arp_notify = 0
net.ipv4.conf.lo.bootp_relay = 0
net.ipv4.conf.lo.disable_policy = 1
net.ipv4.conf.lo.disable_xfrm = 1
net.ipv4.conf.lo.drop_gratuitous_arp = 0
net.ipv4.conf.lo.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.lo.force_igmp_version = 0
net.ipv4.conf.lo.forwarding = 1
net.ipv4.conf.lo.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.lo.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.lo.ignore_routes_with_linkdown = 0
net.ipv4.conf.lo.log_martians = 0
net.ipv4.conf.lo.mc_forwarding = 0
net.ipv4.conf.lo.medium_id = 0
net.ipv4.conf.lo.promote_secondaries = 0
net.ipv4.conf.lo.proxy_arp = 0
net.ipv4.conf.lo.proxy_arp_pvlan = 0
net.ipv4.conf.lo.route_localnet = 0
net.ipv4.conf.lo.rp_filter = 0
net.ipv4.conf.lo.secure_redirects = 1
net.ipv4.conf.lo.send_redirects = 1
net.ipv4.conf.lo.shared_media = 1
net.ipv4.conf.lo.src_valid_mark = 0
net.ipv4.conf.lo.tag = 0
net.ipv4.conf.ppp0.accept_local = 0
net.ipv4.conf.ppp0.accept_redirects = 1
net.ipv4.conf.ppp0.accept_source_route = 1
net.ipv4.conf.ppp0.arp_accept = 0
net.ipv4.conf.ppp0.arp_announce = 0
net.ipv4.conf.ppp0.arp_filter = 0
net.ipv4.conf.ppp0.arp_ignore = 0
net.ipv4.conf.ppp0.arp_notify = 0
net.ipv4.conf.ppp0.bootp_relay = 0
net.ipv4.conf.ppp0.disable_policy = 0
net.ipv4.conf.ppp0.disable_xfrm = 0
net.ipv4.conf.ppp0.drop_gratuitous_arp = 0
net.ipv4.conf.ppp0.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.ppp0.force_igmp_version = 0
net.ipv4.conf.ppp0.forwarding = 1
net.ipv4.conf.ppp0.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.ppp0.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.ppp0.ignore_routes_with_linkdown = 0
net.ipv4.conf.ppp0.log_martians = 0
net.ipv4.conf.ppp0.mc_forwarding = 0
net.ipv4.conf.ppp0.medium_id = 0
net.ipv4.conf.ppp0.promote_secondaries = 0
net.ipv4.conf.ppp0.proxy_arp = 0
net.ipv4.conf.ppp0.proxy_arp_pvlan = 0
net.ipv4.conf.ppp0.route_localnet = 0
net.ipv4.conf.ppp0.rp_filter = 1
net.ipv4.conf.ppp0.secure_redirects = 1
net.ipv4.conf.ppp0.send_redirects = 1
net.ipv4.conf.ppp0.shared_media = 1
net.ipv4.conf.ppp0.src_valid_mark = 0
net.ipv4.conf.ppp0.tag = 0
net.ipv4.conf.tun13.accept_local = 0
net.ipv4.conf.tun13.accept_redirects = 1
net.ipv4.conf.tun13.accept_source_route = 1
net.ipv4.conf.tun13.arp_accept = 0
net.ipv4.conf.tun13.arp_announce = 0
net.ipv4.conf.tun13.arp_filter = 0
net.ipv4.conf.tun13.arp_ignore = 0
net.ipv4.conf.tun13.arp_notify = 0
net.ipv4.conf.tun13.bootp_relay = 0
net.ipv4.conf.tun13.disable_policy = 0
net.ipv4.conf.tun13.disable_xfrm = 0
net.ipv4.conf.tun13.drop_gratuitous_arp = 0
net.ipv4.conf.tun13.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.tun13.force_igmp_version = 0
net.ipv4.conf.tun13.forwarding = 1
net.ipv4.conf.tun13.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.tun13.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.tun13.ignore_routes_with_linkdown = 0
net.ipv4.conf.tun13.log_martians = 0
net.ipv4.conf.tun13.mc_forwarding = 0
net.ipv4.conf.tun13.medium_id = 0
net.ipv4.conf.tun13.promote_secondaries = 0
net.ipv4.conf.tun13.proxy_arp = 0
net.ipv4.conf.tun13.proxy_arp_pvlan = 0
net.ipv4.conf.tun13.route_localnet = 0
net.ipv4.conf.tun13.rp_filter = 1
net.ipv4.conf.tun13.secure_redirects = 1
net.ipv4.conf.tun13.send_redirects = 1
net.ipv4.conf.tun13.shared_media = 1
net.ipv4.conf.tun13.src_valid_mark = 0
net.ipv4.conf.tun13.tag = 0
net.ipv4.conf.tunl0.accept_local = 0
net.ipv4.conf.tunl0.accept_redirects = 1
net.ipv4.conf.tunl0.accept_source_route = 1
net.ipv4.conf.tunl0.arp_accept = 0
net.ipv4.conf.tunl0.arp_announce = 0
net.ipv4.conf.tunl0.arp_filter = 0
net.ipv4.conf.tunl0.arp_ignore = 0
net.ipv4.conf.tunl0.arp_notify = 0
net.ipv4.conf.tunl0.bootp_relay = 0
net.ipv4.conf.tunl0.disable_policy = 0
net.ipv4.conf.tunl0.disable_xfrm = 0
net.ipv4.conf.tunl0.drop_gratuitous_arp = 0
net.ipv4.conf.tunl0.drop_unicast_in_l2_multicast = 0
net.ipv4.conf.tunl0.force_igmp_version = 0
net.ipv4.conf.tunl0.forwarding = 1
net.ipv4.conf.tunl0.igmpv2_unsolicited_report_interval = 10000
net.ipv4.conf.tunl0.igmpv3_unsolicited_report_interval = 1000
net.ipv4.conf.tunl0.ignore_routes_with_linkdown = 0
net.ipv4.conf.tunl0.log_martians = 0
net.ipv4.conf.tunl0.mc_forwarding = 0
net.ipv4.conf.tunl0.medium_id = 0
net.ipv4.conf.tunl0.promote_secondaries = 0
net.ipv4.conf.tunl0.proxy_arp = 0
net.ipv4.conf.tunl0.proxy_arp_pvlan = 0
net.ipv4.conf.tunl0.route_localnet = 0
net.ipv4.conf.tunl0.rp_filter = 1
net.ipv4.conf.tunl0.secure_redirects = 1
net.ipv4.conf.tunl0.send_redirects = 1
net.ipv4.conf.tunl0.shared_media = 1
net.ipv4.conf.tunl0.src_valid_mark = 0
net.ipv4.conf.tunl0.tag = 0
net.ipv4.fib_multipath_use_neigh = 0
net.ipv4.fwmark_reflect = 0
net.ipv4.icmp_echo_ignore_all = 0
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_errors_use_inbound_ifaddr = 0
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.icmp_msgs_burst = 50
net.ipv4.icmp_msgs_per_sec = 1000
net.ipv4.icmp_ratelimit = 1000
net.ipv4.icmp_ratemask = 6168
net.ipv4.igmp_link_local_mcast_reports = 1
net.ipv4.igmp_max_memberships = 20
net.ipv4.igmp_max_msf = 10
net.ipv4.igmp_qrv = 2
net.ipv4.inet_peer_maxttl = 600
net.ipv4.inet_peer_minttl = 120
net.ipv4.inet_peer_threshold = 65664
net.ipv4.ip_default_ttl = 64
net.ipv4.ip_dynaddr = 0
net.ipv4.ip_early_demux = 1
net.ipv4.ip_forward = 1
net.ipv4.ip_forward_use_pmtu = 0
net.ipv4.ip_local_port_range = 32768 60999
net.ipv4.ip_local_reserved_ports =
net.ipv4.ip_no_pmtu_disc = 0
net.ipv4.ip_nonlocal_bind = 0
net.ipv4.ipfrag_high_thresh = 4194304
net.ipv4.ipfrag_low_thresh = 3145728
net.ipv4.ipfrag_max_dist = 64
net.ipv4.ipfrag_secret_interval = 0
net.ipv4.ipfrag_time = 30
net.ipv4.neigh.default.anycast_delay = 100
net.ipv4.neigh.default.app_solicit = 0
net.ipv4.neigh.default.base_reachable_time_ms = 30000
net.ipv4.neigh.default.delay_first_probe_time = 5
net.ipv4.neigh.default.gc_interval = 30
net.ipv4.neigh.default.gc_stale_time = 60
net.ipv4.neigh.default.gc_thresh1 = 128
net.ipv4.neigh.default.gc_thresh2 = 512
net.ipv4.neigh.default.gc_thresh3 = 1024
net.ipv4.neigh.default.locktime = 100
net.ipv4.neigh.default.mcast_resolicit = 0
net.ipv4.neigh.default.mcast_solicit = 3
net.ipv4.neigh.default.proxy_delay = 80
net.ipv4.neigh.default.proxy_qlen = 64
net.ipv4.neigh.default.retrans_time_ms = 1000
net.ipv4.neigh.default.ucast_solicit = 3
net.ipv4.neigh.default.unres_qlen = 31
net.ipv4.neigh.default.unres_qlen_bytes = 65536
net.ipv4.neigh.ens3.anycast_delay = 100
net.ipv4.neigh.ens3.app_solicit = 0
net.ipv4.neigh.ens3.base_reachable_time_ms = 30000
net.ipv4.neigh.ens3.delay_first_probe_time = 5
net.ipv4.neigh.ens3.gc_stale_time = 60
net.ipv4.neigh.ens3.locktime = 100
net.ipv4.neigh.ens3.mcast_resolicit = 0
net.ipv4.neigh.ens3.mcast_solicit = 3
net.ipv4.neigh.ens3.proxy_delay = 80
net.ipv4.neigh.ens3.proxy_qlen = 64
net.ipv4.neigh.ens3.retrans_time_ms = 1000
net.ipv4.neigh.ens3.ucast_solicit = 3
net.ipv4.neigh.ens3.unres_qlen = 31
net.ipv4.neigh.ens3.unres_qlen_bytes = 65536
net.ipv4.neigh.ens7.anycast_delay = 100
net.ipv4.neigh.ens7.app_solicit = 0
net.ipv4.neigh.ens7.base_reachable_time_ms = 30000
net.ipv4.neigh.ens7.delay_first_probe_time = 5
net.ipv4.neigh.ens7.gc_stale_time = 60
net.ipv4.neigh.ens7.locktime = 100
net.ipv4.neigh.ens7.mcast_resolicit = 0
net.ipv4.neigh.ens7.mcast_solicit = 3
net.ipv4.neigh.ens7.proxy_delay = 80
net.ipv4.neigh.ens7.proxy_qlen = 64
net.ipv4.neigh.ens7.retrans_time_ms = 1000
net.ipv4.neigh.ens7.ucast_solicit = 3
net.ipv4.neigh.ens7.unres_qlen = 31
net.ipv4.neigh.ens7.unres_qlen_bytes = 65536
net.ipv4.neigh.lo.anycast_delay = 100
net.ipv4.neigh.lo.app_solicit = 0
net.ipv4.neigh.lo.base_reachable_time_ms = 30000
net.ipv4.neigh.lo.delay_first_probe_time = 5
net.ipv4.neigh.lo.gc_stale_time = 60
net.ipv4.neigh.lo.locktime = 100
net.ipv4.neigh.lo.mcast_resolicit = 0
net.ipv4.neigh.lo.mcast_solicit = 3
net.ipv4.neigh.lo.proxy_delay = 80
net.ipv4.neigh.lo.proxy_qlen = 64
net.ipv4.neigh.lo.retrans_time_ms = 1000
net.ipv4.neigh.lo.ucast_solicit = 3
net.ipv4.neigh.lo.unres_qlen = 31
net.ipv4.neigh.lo.unres_qlen_bytes = 65536
net.ipv4.neigh.ppp0.anycast_delay = 100
net.ipv4.neigh.ppp0.app_solicit = 0
net.ipv4.neigh.ppp0.base_reachable_time_ms = 30000
net.ipv4.neigh.ppp0.delay_first_probe_time = 5
net.ipv4.neigh.ppp0.gc_stale_time = 60
net.ipv4.neigh.ppp0.locktime = 100
net.ipv4.neigh.ppp0.mcast_resolicit = 0
net.ipv4.neigh.ppp0.mcast_solicit = 3
net.ipv4.neigh.ppp0.proxy_delay = 80
net.ipv4.neigh.ppp0.proxy_qlen = 64
net.ipv4.neigh.ppp0.retrans_time_ms = 1000
net.ipv4.neigh.ppp0.ucast_solicit = 3
net.ipv4.neigh.ppp0.unres_qlen = 31
net.ipv4.neigh.ppp0.unres_qlen_bytes = 65536
net.ipv4.neigh.tun13.anycast_delay = 100
net.ipv4.neigh.tun13.app_solicit = 0
net.ipv4.neigh.tun13.base_reachable_time_ms = 30000
net.ipv4.neigh.tun13.delay_first_probe_time = 5
net.ipv4.neigh.tun13.gc_stale_time = 60
net.ipv4.neigh.tun13.locktime = 100
net.ipv4.neigh.tun13.mcast_resolicit = 0
net.ipv4.neigh.tun13.mcast_solicit = 3
net.ipv4.neigh.tun13.proxy_delay = 80
net.ipv4.neigh.tun13.proxy_qlen = 64
net.ipv4.neigh.tun13.retrans_time_ms = 1000
net.ipv4.neigh.tun13.ucast_solicit = 3
net.ipv4.neigh.tun13.unres_qlen = 31
net.ipv4.neigh.tun13.unres_qlen_bytes = 65536
net.ipv4.neigh.tunl0.anycast_delay = 100
net.ipv4.neigh.tunl0.app_solicit = 0
net.ipv4.neigh.tunl0.base_reachable_time_ms = 30000
net.ipv4.neigh.tunl0.delay_first_probe_time = 5
net.ipv4.neigh.tunl0.gc_stale_time = 60
net.ipv4.neigh.tunl0.locktime = 100
net.ipv4.neigh.tunl0.mcast_resolicit = 0
net.ipv4.neigh.tunl0.mcast_solicit = 3
net.ipv4.neigh.tunl0.proxy_delay = 80
net.ipv4.neigh.tunl0.proxy_qlen = 64
net.ipv4.neigh.tunl0.retrans_time_ms = 1000
net.ipv4.neigh.tunl0.ucast_solicit = 3
net.ipv4.neigh.tunl0.unres_qlen = 31
net.ipv4.neigh.tunl0.unres_qlen_bytes = 65536
net.ipv4.ping_group_range = 1 0
net.ipv4.route.error_burst = 1250
net.ipv4.route.error_cost = 250
net.ipv4.route.gc_elasticity = 8
net.ipv4.route.gc_interval = 60
net.ipv4.route.gc_min_interval = 0
net.ipv4.route.gc_min_interval_ms = 500
net.ipv4.route.gc_thresh = -1
net.ipv4.route.gc_timeout = 300
net.ipv4.route.max_size = 2147483647
net.ipv4.route.min_adv_mss = 256
net.ipv4.route.min_pmtu = 552
net.ipv4.route.mtu_expires = 600
net.ipv4.route.redirect_load = 5
net.ipv4.route.redirect_number = 9
net.ipv4.route.redirect_silence = 5120
net.ipv4.tcp_abort_on_overflow = 0
net.ipv4.tcp_adv_win_scale = 1
net.ipv4.tcp_allowed_congestion_control = cubic reno
net.ipv4.tcp_app_win = 31
net.ipv4.tcp_autocorking = 1
net.ipv4.tcp_available_congestion_control = cubic reno
net.ipv4.tcp_base_mss = 1024
net.ipv4.tcp_challenge_ack_limit = 1000
net.ipv4.tcp_congestion_control = cubic
net.ipv4.tcp_dsack = 1
net.ipv4.tcp_early_retrans = 3
net.ipv4.tcp_ecn = 2
net.ipv4.tcp_ecn_fallback = 1
net.ipv4.tcp_fack = 1
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_fastopen_key = 3e172702-0b5a107e-7aeb9159-53ffe7f7
net.ipv4.tcp_fin_timeout = 60
net.ipv4.tcp_frto = 2
net.ipv4.tcp_fwmark_accept = 0
net.ipv4.tcp_invalid_ratelimit = 500
net.ipv4.tcp_keepalive_intvl = 75
net.ipv4.tcp_keepalive_probes = 9
net.ipv4.tcp_keepalive_time = 7200
net.ipv4.tcp_l3mdev_accept = 0
net.ipv4.tcp_limit_output_bytes = 262144
net.ipv4.tcp_low_latency = 1
net.ipv4.tcp_max_orphans = 2048
net.ipv4.tcp_max_reordering = 300
net.ipv4.tcp_max_syn_backlog = 128
net.ipv4.tcp_max_tw_buckets = 2048
net.ipv4.tcp_mem = 5298 7067 10596
net.ipv4.tcp_min_rtt_wlen = 300
net.ipv4.tcp_min_tso_segs = 2
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_mtu_probing = 0
net.ipv4.tcp_no_metrics_save = 0
net.ipv4.tcp_notsent_lowat = -1
net.ipv4.tcp_orphan_retries = 0
net.ipv4.tcp_pacing_ca_ratio = 120
net.ipv4.tcp_pacing_ss_ratio = 200
net.ipv4.tcp_probe_interval = 600
net.ipv4.tcp_probe_threshold = 8
net.ipv4.tcp_recovery = 1
net.ipv4.tcp_reordering = 3
net.ipv4.tcp_retrans_collapse = 1
net.ipv4.tcp_retries1 = 3
net.ipv4.tcp_retries2 = 15
net.ipv4.tcp_rfc1337 = 0
net.ipv4.tcp_rmem = 4096 87380 16777216
net.ipv4.tcp_sack = 0
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_stdurg = 0
net.ipv4.tcp_syn_retries = 6
net.ipv4.tcp_synack_retries = 5
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_thin_dupack = 0
net.ipv4.tcp_thin_linear_timeouts = 0
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_tso_win_divisor = 3
net.ipv4.tcp_tw_recycle = 0
net.ipv4.tcp_tw_reuse = 0
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_wmem = 4096 16384 16777216
net.ipv4.tcp_workaround_signed_windows = 0
net.ipv4.udp_mem = 10599 14134 21198
net.ipv4.udp_rmem_min = 4096
net.ipv4.udp_wmem_min = 4096
net.ipv4.xfrm4_gc_thresh = 2147483647
Hi,
I'm experiencing weird RTT on Linux. Some extra latency exists when ping through the sstp tunnel. And this latency becomes fluctuating randomly, from the lowest to thousands, when there are another streams running through the tunnel, eg, if files being download through the sstp even at low speed.
Physical delay between client and server is only 20ms. The high and unstable latency makes it unpractical on use. Could you look into this problem please? My network only allows SSTP, any other types of tunnel are banned so my server relies on it.
Notice that this problem doesn't exists on Windows with the same sstp accounts. Remote SSTP Server bandwidth is over 40Mbps and I'm the only person using it. My Linux has no problem with pulling files directly at high speed (4MB/s
) from the remote server.
I have tried to reboot my Linux several times and it doesn't fix the problem.
system configurations:
Ubuntu 16.04 LTS
sstp-client V1.0.11 (build from sourceforge.net package)
OpenSSL 1.0.2g 1 Mar 2016
Kernel 4.8.0-41-generic
CPU load is very low, under 10%
ppp configurations
Some highlights on some sysctl config:
full sysctl: