search for: pmtu

While working on SPTPS UDP relaying I realized that there is one issue I didn't account for, which is that the sending node only knows the PMTU to the first relay node. It doesn't know the PMTU of the entire relay path beyond the first hop, because the relay nodes don't provide their own PMTU information over the metaprotocol. Now, in the legacy protocol this is not really an issue, because TCP MSS clamping (which is really what m...

Hi Guus, while checking the source code, I stumbled upon PMTU Discovery. I've got a question regarding the process of sending/receiving PMTU packets. As I understand, the packet flow is like this: 1 .Tinc creates a packet with a specific payload length to send it as an PMTU probe. (The data part is just some random bytes.) 2. This...

Hi all, I have two nodes, connected to a switch, using Tinc 1.1 from git. They connect each other with sptps, and to other nodes in the Internet with old protocol because they have Tinc 1.0. There is no problem with remote nodes, but between my 2 local nodes, they see 1518 PMTU. But local network is 1500 MTU !!! So nodes can ping each other but larger data does not go. test1=sllm1 test2=sllm2 test1:/usr/src/tinc# tinc -n coppint info sllm2 Node: sllm2 Address: 192.168.0.202 port 655 Online since: 2014-02-25 13:36:39 Status: validkey visited reachable...

...384]: total bytes in: 2294 2011-08-16 14:24:41 tinc.ci1070300036[14384]: total bytes out: 13329 2011-08-16 14:24:41 tinc.ci1070300036[14384]: Nodes: 2011-08-16 14:24:41 tinc.ci1070300036[14384]: ca1070300036 at (null) cipher 0 digest 0 maclength 0 compression 0 options 0 status 0020 nexthop - via - pmtu 1518 (min 0 max 1518) 2011-08-16 14:24:41 tinc.ci1070300036[14384]: ca1070300362 at (null) cipher 0 digest 0 maclength 0 compression 0 options 0 status 0020 nexthop - via - pmtu 1518 (min 0 max 1518) 2011-08-16 14:24:41 tinc.ci1070300036[14384]: ci1070300036 at MYSELF cipher 0 digest 0 maclength 0...

...eing routed via HostC, all the way on the other side of the world. This seems like a strange decision giving that the direct path is clearly faster. What's the best way to debug this, can I prove that the routing is indirect? The only potential cause I can see in the below dumps is that the PMTU from HostA to HostB is very small. Maybe tinc is deciding that the path with higher initial MTU is better quality -- even though the PMTU from HostC to HostB is small as well? Reachability for all nodes is "directly with UDP". [HostA]#: tinc -n mesh1 dump nodes HostA id e45fbb0b9280 a...

Dear Guus, while improving the PMTU Discovery algorithm, I found the following behavior in the method "send_udppacket": 1) The code checks, whether the data size is smaller than the MTU, thus if it fits into a single UDP packet. If not, you send the packet via TCP. 2) The data is compressed, changing its siz...

On Wed, May 13, 2015 at 04:41:30PM +0200, Florent B wrote: > I have MTU problems when all these conditions are true: > - a client is running Ubuntu (ICMP messages about PMTUd are ignored on > it by default) I have no experience with Ubuntu, but I find it hard to believe it would block ICMP Fragmentation Needed packets out of the box. > - a client is accessing us from a particular network > - the client is accessing a backend VM which is not on the load-balan...

...ded packets out of the box. > > I can confirm you that this is the case. Ubuntu ignores those ICMP > packets... :( (rp_filter settings) > > You can see it here : https://mellowd.co.uk/ccie/?p=5662 Ok... well that's just silly then. > > Can you check what tinc thinks the PMTU is in each of these cases? With > > tinc 1.0.24, you do "tincd -n <netname> -kUSR2", and it will send a list > > of nodes to the syslog. The MTU should be in it. > > For the 3 servers, Tinc reports 1459 as pmtu for each other. Ok. And for the client? > Someth...

...entries in our logs: Oct 14 08:00:50 mailsrv sendmail[2024]: m9ED0Yf5002021: to=<customername at customer.org>, delay=00:00:16, xdelay=00:00:16, mailer=esmtp, pri=42476, relay=mail.customer.org. [XX.XX.XX.XX], dsn=4.0.0, stat=Deferred: Connection reset by mail.customer.org. I have disabled pmtu discovery on our routers as well as on all our outbound mail servers. Is there anything else I can do on our side to help the situation?

...(81.10.. port 57004) here's the output of USR2 on zzzzz: Statistics for Generic BSD tun device /dev/tun1: total bytes in: 57750 total bytes out: 86210 Nodes: bbbbb at 199.167.. port 655 cipher 427 digest 64 maclength 4 compression 0 options c status 001a nexthop bbbbb via bbbbb pmtu 1518 (min 0 max 1518) yyyyy at 86.56.. port 655 cipher 0 digest 0 maclength 0 compression 0 options c status 0018 nexthop bbbbb via yyyyy pmtu 1518 (min 0 max 1518) aaaaa at 188.40.. port 655 cipher 427 digest 64 maclength 4 compression 0 options c status 001a nexthop aaaaa via aaaaa pmtu 1518 (m...

...ons c weight 87 tinc.rgdevvpn> From this screen, it seems that MIKEHOMEPC is only accessible via VPS01PP? tinc.rgdevvpn> dump reachable nodes MIKEHOMEPC at x.241.100.155 port 655 cipher 91 digest 64 maclength 4 compression 0 options c status 0018 nexthop VPS01PP via MIKEHOMEPC distance 2 pmtu 1451 (min 0 max 1518) MIKELAPTOP at x.241.100.155 port 655 cipher 91 digest 64 maclength 4 compression 0 options c status 0018 nexthop VPS01PP via MIKELAPTOP distance 2 pmtu 1459 (min 0 max 1518) MIKEWORKPC at x.62.187.113 port 655 cipher 91 digest 64 maclength 4 compression 0 options c status 0...

...Could you suggest me something to restrict the problem? > Currently, I think the problem can be: > > 1) on Asterisk > 2) on my Gateway/Firewall A couple of years ago I added this entry in my firewall: /sbin/iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j TCPMSS --clamp-mss-to-pmtu since I had the problem downloading data from an Internet site using my tablet. I found this site explaining that: https://lartc.org/howto/lartc.cookbook.mtu-mss.html I really forgot this entry, but now I checked all entries in my Firewall, and I see it, with my remark... Now, the last lin...

...er without any packet loss, hopefully at LAN latencies. Actual result: - I'm experiencing packet loss every (PingInterval) seconds. Each packet loss "episode" lasts roughly 1 second and during that time all packets are lost. Apparently it happens each time the nodes are exchanging PMTU probes. Packet loss correlates with "Sending/Got MTU probe" messages. It also materializes in the form of "Received UDP packet from unknown source <LAN Address>" messages. - There seems to be some "flapping" with regard to the local host discovery itself, mea...

On Thu, May 14, 2015 at 10:12:40 +0200, Florent B wrote: > On 05/13/2015 05:00 PM, Guus Sliepen wrote: > > I have no experience with Ubuntu, but I find it hard to believe it would > > block ICMP Fragmentation Needed packets out of the box. > > I can confirm you that this is the case. Ubuntu ignores those ICMP > packets... :( (rp_filter settings) > > You can see it

Hello, I try to set up my Linux 2.4.x system to respond by "ICMP Destination Unreachable message" subtype 4 ("fragmentation needed and DF set") in order to support the Path MTU Discovery (RFC 1191) as a router. There is any /proc/xxx parameter to do this? Thanks Mugur _______________________________________________ LARTC mailing list LARTC@mailman.ds9a.nl

https://bugzilla.netfilter.org/show_bug.cgi?id=662 Phil Oester <netfilter at linuxace.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|REOPENED |RESOLVED CC| |netfilter at linuxace.com Resolution|

Would you mind repeating the test with canreinvite=no set for all you phones and mobile phones? What is your upload bitrate? Is it guaranteed? I would try also to test the PMTU: Try: ping -M do -s 2000 ${ip address of the sip server} You should receive icmp asking for lowering the packet size. The LTE phones could have lower MTU and thus overcome PMTU problem. Marek 2020-06-22 21:48 GMT+02:00, Luca Bertoncello <lucabert at lucabert.de>: > A thing I forgot...

Hi everyone, you can find the current version of my enhanced tinc using subversion: svn://tardyon.mon-clan.de/tinc I allowed anonymous read access, so feel free to download the sources. Unfortunately, my enhancements are based on a rather old git-checkout from Guus. The version should run under windows and Debian/Ubuntu. Best, Daniel -----Original Message----- From: folkert [mailto:folkert

...there is an IP/UDP frame size issue because the firewall software I use, SoftPerfect Personal Firewall, is reporting this error in it's logs when I try to do something like a file transfer. I am able to ping between hosts with packet sizes up to 1417 bytes. I did some testing with setting the PMTU value and setting PMTUDiscover = no, however it had no affect. Both hosts are running Windows XP. Host files; Address = argyle.thruhere.net Port = 8002 IndirectData = yes # PMTU = 1024 # PMTUDiscovery = no #TCPOnly = Yes -----BEGIN RSA PUBLIC KEY----- Address = nixon.endoftheinternet.org Port =...

...then looked at curl and realized the problem is probably not MTU related. I appreciate any thoughts and help. Here are my current configs: Server A Conf: Name = serverA Device = /dev/net/tun Address Family = ipv4 Server A host: Address = xx.xx.xx.xx Subnet = 192.168.0.10 Subnet = 10.75.70.0/24 PMTU = 1436 ClampMSS = yes PMTUDiscovery = yes Server A TincUp: ip link set $INTERFACE up ip addr add 192.168.0.10 dev $INTERFACE ip route add 192.168.0.0/24 dev $INTERFACE ip route add 192.168.1.0/24 dev $INTERFACE Server B Conf: Name = khwisnmp Device = /dev/net/tun Address Family = ipv4 Connect...