Smb over ipsec tunnel Apr 15, 2025 · The Server Message Block (SMB) protocol is widely used in enterprise environments for file sharing. If there’s a deny rule at the end of the security rulebase, intrazone traffic is blocked unless otherwise allowed. Oct 27, 2017 · 18 1098 March 2, 2016 VPN file transfer fails in one way Networking general-networking , draytek , file-sharing , question 3 536 March 3, 2022 SMB file transfer over IPsec is crazy slow Networking general-networking , question 6 2661 October 7, 2021 ipsec site to site tunnel drops after 100MB circa Networking general-networking , question 12 Mar 30, 2021 · SMB networking is a pretty often used way to spread malware across networks. For some reason, when I try to download files from our file server (anything 80 MB and above), my download speeds average out to 2 MBps. May 15, 2023 · I have tried SMB/CIFS data transfer through the tunnel and FTP transfer outside of the tunnel and both of them show similar transfer speed. We have an SSL VPN configured on a FortiGate VM on firmware 7. ScopeFortiGate. All I can achive is GRE traffic seen within vpnt interface, but it seems to blackhole traffic since I cant see any IPSEC traffic going out the gateway. 20. I can ping IP, nslookup and ping hostname of the PC. And yes, if you use AES GCM with SafeXcel on ARM, you got stuck after som Time with the entire IPsec Stack. I am running a pfSense on each end, both running on VMWare with 2 CPU's and 4GB RAM with the VMWare tool package installed utilizing VMXNet3 NICs. Sep 3, 2025 · Filter IPsec VTI and Transport on assigned interfaces, block all tunnel mode traffic: Enables firewall rules for assigned VTI and transport mode interfaces, NAT on VTI interfaces, and reply-to for rules on assigned VTI interface tabs. When running SMB over slow, higher latency links you will get slow performance out of the VPN. I have a 500Mbps pipe on one end and practically unlimited (1Gbps+) on the other. When Tunnels are created and put to use, you can keep track of their normal function, so that possible malfunctions and connectivity problems can be Oct 8, 2019 · Assuming you're using IPSEC, have you investigated which protocols will grant the greater speeds? 3DES vs AES for example? There appear to be a lot of variables here making it difficult to pin down exactly where you may have a speed issue. Synonym: Site-to-Site VPN. I've also read that file share/smb/cifs just functions What is the latency between the two offices ? Second question is what protocol are you using to transfer data ? SMB for example is so slow over a “high latency” link. This issue does not affect connectivity between local network computers and remote machines—only the firewall itself loses connection. Feb 26, 2025 · some of the common factors affecting the IPSec VPN throughput and its limitations. 3 MR-3-Build427) and machines on the other side of the IPSec S2S VPN tunnel. 2-RELEASE) but instead of relying on broadcasting and using 'Network Aug 27, 2024 · GRE over IPSEC Hi, Has anyone managed to build GRE through an IPSEC tunnel? I tried both: domain and route based IPSEC. Go to User & Authentication → User Definition → Create New. However, SMB is known for being extremely sensitive to network latency and fragmentation, making it a challenging protocol to optimize over wide-area networks (WANs), especially when IPSec tunnels, cloud security platforms like Cloudflare ZTNA, and next-generation firewalls such as FortiGate are May 14, 2024 · Site to Site VPN An encrypted tunnel between two or more Security Gateways. I run my NAS Backups over the Tunnel, with the Upload limiting around about 50MBit/s. Aug 15, 2019 · We have fortigate 300E ( india office) & 100D (US office) both are connected via IPSEC tunnel. Filtered on IPsec Tab By default, traffic passed inside a tunnel from the remote end is filtered by rules configured under Firewall > Rules on the IPsec tab (enc0). VPN tunnels were set up using the FortiGate VPN wizard template. The only things I know to try are: Reduce the MTU in the tunnel interface associated with the ipsec connection. I only mention file server because that's what i'm running the iperf3 host on (server 2022 on a fast SSD 10gb based server). We have a windows file server in Site 1, a Nas in Site 2. Solution The SMB protocol is designed for local file sharing with low latency. Jul 13, 2015 · Hello! We have network issue with extremely slow copy speed via GRE or IPIP IPsec tunnel. For example, our Cisco router provides IPSec / UDP and IPSec / TCP. There is a pass any/any rule set up on both the LAN and IPSEC interfaces in the firewall rules section. Aug 11, 2024 · here comes yet another (i suspect) MTU issue. EDIT: To check if it's a MTU problem, lower the MTU of PC and the server to 1200 and retry to copy using SMB. Site B: Cisco RV340 with the same type of local setup, a LAN and a WAN leg. I'm having a weird issue with the IPsec VPN between two sites. Both locations have 101F for the device. When you employ this protocol across long distances, the Hi Everyone, I've been banging my head against this issue for about 3 weeks now. Oct 26, 2021 · The tunnel interface for this particular site-to-site is also using default MTU. both sites have: hap ac2 with a NAS attached on LAN. , VLAN interface, Physical interface) except for the Loopback interface, the traffic for IKE (tunnel set-up/control plane) and IPSec (encrypted data packet/data plane) should exit out via the same interface on which the IPSec tunnel is built. Jun 13, 2019 · SMB is a LAN protocol and a pita on WAN. I’ve verified 1500 MTU set on the NIC, switches, and firewall but if I watch Wireshark I see packets getting up in the 2700 plus range going out. In US site I have a file server which needs to be accessed from EU site. Did anyone use any WAN Acc solutions with Azure? Some recommendations SMB over VPN performance boost I am actually posting here with a positive finding for once! If you use SMB over a VPN with the Windows VPN client and you set the rule governing the SMB traffic to proxy-based inspection mode with a security profile that utilizes it like AV, then you can see a dramatic improvement on SMB throughput to the client. Monitoring VPN Tunnels This section describes how to monitor VPN tunnels. In this Jul 8, 2019 · However, now I have two Tl-R600VPN routers successfully connect with a IPSEC site to site tunnel. Iperf shows 44 mbps. AES256-SHA512. Mar 9, 2023 · troubleshooting for slow speed issues over the IPsec tunnel using the iPerf tool. Try to change the MTU, if this doesn't fix the problem good luck. The site A is connected to a 1G symmetrical fiber service and Site B is connected to a 500 Symmetrical fiber. Scope FortiGate and all FortiOS Platforms. SMB 1. 30 we observed better copy speed via SCP on linux machines. We have had incredibly slow download and upload speeds to the server for all file types Hello friends, We are trying to squeeze out every bit of performance from SMB over VPN. Then I did some testing and discussed with Fortigate support, he lowered the MTU on both interface of IPSEC tunnel, it starts working now, the MTU I Oct 7, 2021 · I have been experiencing super slow transfer speeds over IPsec using SMB. . 1. What GRE/IPSEC tunnel you mean? If you mea L2TP over IPSEC VPN, TP-LINK SMB Router supports it. Even a slight packet loss or delay in these exchanges can cause noticeable slowdowns. Mar 30, 2020 · Our company recently transferred to fully online from in office due to the current crisis. x. It’s a split tunnel and in general, the connection works great for accessing websites and other things hosted internally but SMB traffic specifically is working like its stuck-on SMB v1 speeds (~300-700K/sec) however it seems fast for a I know it is not a generally recommended practice, but for complicated reasons I have one machine doing backups to a network drive over an ipsec tunnel. P2 esp,3des,sha1, enable keep alive & netbios broadcast) using sonicwall TZ300 (SonicOS Enhanced 5. As IPsec packets travel in the form of ESP (Encapsulated Security Payload) packets that are sent over Sep 30, 2016 · I, too, am seeing poor performance over an IPSEC VPN tunnel. A valid test would be to change/increase the MTU configuration of your interfaces where the IPsec tunnels are bound, an Without the IPSec tunnel it run at 90Mbps in both direction. This Speed is no problem for the 21er, System Load 8-9%, Interrupt 18%. This protocol is used to provide access to files, printers, serial ports and oth Mar 10, 2020 · I have been running into an issue with SMB performance over the ipsec tunnel. Feb 9, 2023 · Solved: hello together I have the following problem over IPSEC VPN the file transfer to a share is very slow. Run a ping test with the largest payload supported by the connection outside the VPN and see if there is any packet loss or other issues. Sep 8, 2018 · - If I do the transfer test over an IPSEC tunnel, I do not have this problem (Tested from an Azure server that links to my on- prem network) - My company network and GP VPN tunnel are not under a heavy load during these tests, in fact I was the only one on the GP VPN during these tests. Therefore, it is highly sensitive to packet loss Oct 6, 2021 · I have been experiencing super slow transfer speeds over IPsec using SMB. I have read several of the articles (most older) where some people have a solu Jun 13, 2019 · Bit lost for ideas on how to fix. Software Blade Specific security solution (module): (1) On a Security Gateway, each Sep 5, 2013 · we are connecting Cisco 887VA router with various other Non-Cisco routers. But if we try to copy any files via SMB on Windows machines – speed is extremely slow. iperf client and server on same lan network, no firewall involved: 900+mbps. thanks This is a known phenomenon. Go to Main Page Feb 21, 2025 · Description: Since updating NSX in our remote Virtual Data Center, we have observed intermittent connectivity loss between our Sophos XGS136 (SFOS 20. 3-encrypted security tunnel like a VPN for the SMB traffic. Page Not Found or Access Denied Sorry, the page you're looking for either doesn't exist or you don't have permission to view it. However, we have a few devices (on the Cisco lan) that provide a web interface (NAS etc) and these are not accessible over the VPN, the connect Oct 17, 2024 · For IKEv1 Phase-2, see Define IPSec Crypto Profiles. SMB file sharing works great on LANs but struggles with VPNs in hybrid work setups, causing productivity issues. 2. The client pc is a standard windows 10 os. Contractions: S2S VPN, S-to-S VPN. Jan 28, 2019 · Question for you Is the SMB traffic encrypted? If it is you might want to do a packet capture to check if you have packets with MTU sizes over the limit of 1500 causing packet drops when it tries to pass trough the IPSEC tunnel. Solution Packets that are too large may be dropped by Internet or private network routers. The bandwidth over the tunnel is topping out at 56Mbits both up and down. Jumbo frames are disabled on the NIC so I’m not sure why SMB can even send over 1500 SMB/CIFS traffic is just difficult to run over ipsec if the link is high latency and/or high packet loss. Solution After verifying the compatibility between FortiGate and FortiClient, look at some recommendations to improve file transfer when connected to SSL VPN: Verify that DTLS is enabled both o Jun 19, 2022 · Troubleshooting VPN Tunnel dropping or not initializing Configuring a Site to Site VPN Policy using Main Mode (Static IP address on both sites)Configuring In general, I rarely use SMB over VPN like because of the same behaviour you have observed. IPSec tunnel mode creates a secure connection between two endpoints by encapsulating packets in an additional IP header. ScopeFortiOS. Nessus flagged any system with it enabled and to disable it, then we did. Meaning people didn't have SMB2/SMB3 which dramatically improved CIFS/SMB performance. the NAS-NAS speed doesn’t exceed 5. The speed fluctuates greatly and typically averages out in the KB speeds. 3b11 and the other has pfSense 1. One of the most widely used protocols for this purpose is the Server Message Block (SMB), which allows for file sharing and access to printers and other network resources. Solution It is necessary to check the status of the speed through the WAN link and then compare it when passing the traffic through the tunnel link. If I tranter SMB I’m getting around 3mBps showing from windows. Scope FortiOS. We are digging into optimization for VPN and so far we only tried disabling bandwidth throttling on high latency network (HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters\DisableBandwidthThrottling). I can access the management webpage of the printer by typing in its IP address, but the phone does not see the printer when trying to print. To get a true performance test, run iPerf from Office A to Office B …. We are able to open the shared folder using map|smb folder. IPSec tunnel mode is the default mode. We have a setup where 2 sites on 50 Mb/s up/down each have an SMB server and are connected via an IPSec VPN (pfSense). Currently we are facing issue when access or open a file located at File server (10. ScopeFortiGate, FortiClient. 0 was really bad about this as it could only read 64k at a time, then it would have to contact the server and ask for the next 64k, etc. x subnet, a few pc with a canon copy Jun 29, 2012 · I did a packet capture while attempting dir \remotehost\sharename and could see that the packets made it over the ipsec interface, but I get an error, The network path was not found. This is a critical problem, as Jul 21, 2025 · Scope FortiGate. That will be affected by which DH algorithms are being used among other things. Over the vpn, SMB traffic in one direction is excellent, in the other its around 5Mb / minute! Http is fine, so its got nothing to do with using TCP, nor the fiber speeds, nor mtu Nov 1, 2024 · With Windows 11 and Windows Server 2022 Datacenter: Azure Edition, you can use SMB over QUIC to connect to file servers in Azure. Oct 22, 2019 · fortigate 200e. iperf3 client to server over the ipsec tunnel: 50-60mbps (regardless of what changes we make in the tunnels). Turn replay protection off on both ends ipsec config. One such configuration is the IPSec mode—tunnel mode or transport mode. The problem is, when writing files from Site 2 to the windows file server in Site 1 we are getting about 1-2MB/minute while in the other direction we are seeing around 300Mb/sec. VPN tunnels are up and we can ping devices on the remote network through the VPN. It hands out a small 25 ipv4 block of ip… Oct 7, 2021 · Start point is a Windows 10 machine just copying files over an IPsec tunnel to a Windows 2012R2 share. May 13, 2024 · how to troubleshoot the slowness in SMB traffic transfer over FortiGate SD-WAN. In this article, we’ll explore the importance of IPsec Dec 13, 2019 · @ tjcooks4829 said in Site to Site IPsec IKEv2 MTU/MSS clarification: Guidance on how I can end this misery and get back to a productive life? A couple pointed questions: I've read that poking at the IPSEC config too much can cause problems that only a factory reset will cure. This chattiness results in a lot of overhead, and the VPN would have to encrypt and decrypt each packet. Feb 19, 2017 · Hi all, I have two sites US and Europe. I have also set up an OpenVPN tunnel to test and it works as expected with Windows and SMB, but would prefer to try to use IPSec due to potentially better performance. Jul 25, 2013 · J jamesbond Jan 29, 2016, 2:16 AM I also have a very similar problem with slow traffic over IPsec tunnel, I am pretty newish to networking but want to know if this is normal behavior for a IPsec connection Site A – Data center has 100/100mb in and out Site B – Home, has virgin media fibre broadband 150mb line gives me around 10mb upload max. 1 IPsec VPN, dependent on UDP, can run over TCP. 10. It applies to all VPN types, such as remote access and site-to-site IPsec/SSL VPN. Solution When an IPSec tunnel is configured on an interface (i. Once you can verify the Internet connection between devices, then check the same things inside the VPN connection. Now, knowing, and reading that SMB suffers from high latency connections I've tried a scp of a small file (190kb) while connected via Mobile VPN and the site-to-site with those results below: Jan 31, 2021 · Now, knowing, and reading that SMB suffers from high latency connections I've tried a scp of a small file (190kb) while connected via Mobile VPN and the site-to-site with those results below: Mar 2, 2020 · The entire SMB conversation – negotiate capabilities, authentication, authorization, message bodies – all occur inside the QUIC layer, just like if the user was in an IPSEC or VPN tunnel. This helped Mar 4, 2019 · Fortinet to Fortinet, 100E to 60E, IPSec Tunnel, gigabit connection on the 100E and 400mbit on the 60E. Apr 24, 2025 · (Probably mostly when using an ipsec type tunnel) ivicask April 24, 2025, 12:19pm 8 I did try Wireguard, speeds were even worst, tried with multiple MTUs. We all know that SMB is very chit-chatty so latency really kills the performance. Upload speeds are about 27 mbps Sep 26, 2025 · Hello, due to massive performance issues when using SMB over IPSec I tried Wireguard Site2Site. So I setup a site to site vpn (main mode, group 2, 3des,sha1. Thank you Regards, RTuesca Mar 14, 2024 · In this installment, we dive into the crucial aspects of setting up Fortigate firewalls, establishing a secure site-to-site IPsec tunnel, and configuring Cisco switches for optimized network Jun 27, 2013 · We use network drives over vpn at 37 offices in 4 states, and have no firewall issues with the vpn. Whats the VPN throughput on your firewalls and how much OTHER traffic is being pushed over the VPN tunnel while you are doing this? It's quite common to have slow SMB transfer rates over a VPN. DH 19,14. If from the WAN link, the speed is not up to the mar Aug 29, 2023 · Hello All, I am sorry for any ignorance or lack of knowledge on my part. I’ve tried to figure it out and finally got confused, so my tests lost a structure a became a random lock-picking. I can correctly ping the computer that is sharing the folders, and if I type the ip address in the windows explorer I can access it, but it doesn't show up in the network section of windows explorer like it did when connecting via softether. Also, not sure about NetBIOS as a comment or above me mentioned. In high latency or Hi guys, We have been having slow performance issues with SMB traffic that's going over AOVPN (Microsoft Always ON VPN) connections back to our college. See Monitor Your IPSec VPN Tunnel . Tunnel is up, icmp is working fine. The tunnel is up and stable, and traffic can flow both directions just fine, but I can only seem to perform backups if I check the "bypass all ipsec traffic" box Sep 2, 2025 · On This Page IPsec (Tunnel Mode) Captive Portal Firewall Rules Routing Problems Hardware Checksum Offloading Troubleshooting Lost Traffic or Disappearing Packets If there are issues with traffic being lost, or packets that seem to disappear or never show up (or leave) an interface, there are a few potential causes to consider. Packetloss would also slow down IPSec, so I'd go for problems on the line or the nic. We have a primary location with a Local AD server. I used for testing a IPv4 Jun 17, 2025 · File transfer over VPN tunnel is slow in one direction but very fast in the opposite direction Hardware & Infrastructure Networking cisco, question Jul 9, 2019 · SMB is a LAN protocol and a pita on WAN. We have a head office (60F) and branch office (40F) connected with a VPN. Define Security policies to filter and inspect the traffic. Once you have a VPN connection, it is better to connect to a remote server and access the NAS from it. In the Czech Republic, there is a Mikrotik RB4011iGS+ router; in Italy, it’s hard to say. However, SMB is known for being extremely sensitive to network latency and fragmentation, making it a challenging protocol to optimize over wide-area networks (WANs), especially when IPSec tunnels, cloud security platforms like Cloudflare ZTNA, and next-generation firewalls such as FortiGate are May 5, 2025 · the SMB speed related to packet loss and delay in the WAN/IPSec network. Or buy a pair of Mikrotik and use them to open a IPSec tunnel, I think it's the only way to bypass the problem. Try setting this on your IPSEC policies: set tcp-mss-sender 1350 set tcp-mss-receiver 1350 That allows for a little over head for IPSEC encapsulation to keep the mtu under 1500. 8-10o) main office to TZ400 (SonicOS Enhanced 6. IPsec over TCP can help VPN traffic pass through restrictive firewalls, especially when the firewall only allows TCP-based traffic. Please help to put me back on tracks. 3) through IPsec tunnel located at branch (Watchguard). If your endpoint is in China, switch to a CN2 DIA. Seems strange that only SMB, and only SMB on Windows seems to be affected. Ping RTT between the sites is about 30ms. Aug 29, 2017 · [SOLVED] slow IPsec performanceQuote from: mimugmail on August 29, 2017, 06:05:56 PM If you have 25Mbps and a throttle to 1-2Mbps it's mostly packetloss (line, nic, driver etc) and a suboptimal windows size. There's also ways to see if the tunnel is using the ASIC NPU offloads or not. Check your block size server side that SMB is using, as well as ensure the TCP MSS is adjusted on your VPN endpoints to accommodate the IPSEC overhead and not cause excessive fragmentation. If Site A cannot reach Site B, check the Site B firewall log and rules. We currently are using a sonicwall tz400 for our firewall and the Global VPN IPSec tunnel for connecting to the office’s server. 5 on both ends. The situation is: server#1 <> SRX650 <internet/IPSEC VPN> Cisco RV320 <> server#2 On the SRX650 I've lowered the MSS: set security flow tcp-mss ipsec-vpn mss 1350 set security flow tcp-session no-syn-check (this was set for issues with another Dec 1, 2021 · Thank you all for the comments! Thanks to your replies I believe I have traced the problem: the IPSec VPN seems to be forwarding SMB port 139 but not port 445, which is the only port Windows 10 now uses for SMB. x subnet, remote office has a x. Best was with defauts. I did an iperf3 test and it shows that when using TCP protocol, the data transfer speed is extremely minimal but when using UDP connection, the speed is between 890-950 mbps with around 50% datagram loss. Connection speed between sites is 15Mbps Down/Up (Speed is the same in both sites). Any tips on how to improve transfer rates? Sep 2, 2025 · On This Page Tunnel establishes but no traffic passes Some hosts work but not all Connection hangs Disappearing traffic Troubleshooting IPsec Traffic Tunnel establishes but no traffic passes The first place to look if a tunnel comes up but will not pass traffic is the IPsec firewall rules tab. This also allows transport mode to properly filter traffic in both directions, such as with GRE tunnels protected by transport mode IPsec. Sep 3, 2025 · Tunneled IPsec Traffic from Remote to Local The behavior of firewall rules for traffic inside an IPsec tunnel depends on the IPsec Filter Mode option in the Advanced IPsec Settings. After upgrade to latest firmware version 6. May 22, 2019 · SMB performance over VPN is an issue we see periodically at our clients. Windows and remote SMB can be quirky Make sure it's set to internal source "any any" sending all traffic on all ports through the tunnel? Jul 6, 2024 · Allowing remote access SSL VPN traffic over an existing IPsec tunnel In this scenario, it is assumed that the SSL VPN profile is already created to access the local network of the Sophos Firewall. I'm guessing I need to either adjust the MTU on the loopback/tunnel (if I have to adjust on the loopback, I wonder how this will impact all of the other tunnel interfaces also utilizing it) or turn on the TCP MSS adjustment? May 15, 2013 · Hi anyone have issues after migrating from a dedicated point to point link like FR or T1 to a high latency 300ms+ INET IPSEC connection with a SMB file copy ?? attached is a very chatty pcap latency over hi link smb asked 15 May '13, 11:25 franki21 1 1 1 2 accept rate: 0% Aug 31, 2016 · @J69ANT: Hi, Just standard Microsoft file transfers. Link speed US office 10 Mbps down / 3 mbps UP Link speed India office 20 mbps down / 8 mbps now issue is on IPSEC tunnel when i copy file from India office to US office it give me speed around 1 Mbps But Many VPN providers run IPSec over another transmission protocol. Nov 22, 2022 · Hi Everyone-- I'm hoping someone might have a suggestion. These Tunnels ensure secure connections between gateways of an organization and remote access clients. VPN Tunnels Solution VPN Tunnels are secure links between gateways. e. May 27, 2021 · Hi All I cannot RDP nor smb or access resources over an IPSec VPN tunnel between 2 Cisco firepowers, one is 1010 the other 1140 to note: - I can ping fine both ways - ACL not an issue as policy is to allow any port on both ends and ping works - IPSEC configured on both towards Azure VPN gateway, a Synology DS-918+ & SMB Over IPSec I'm currently going a bit crazy trying to figure this one out and hoping someone has come across it before or can help me figure it out. With a continuous ping, if the RTT goes up 10fold during an SMB transfer then it's the upload speed issue. However, when set to Jul 24, 2025 · Learn about SMB over QUIC, a secure alternative to TCP for file sharing in Windows and Windows Server that enables encrypted access to file servers over untrusted networks. Solution The best way to troubleshoot speed-related issues on the IPsec tunnel is to compare the bandwidth over WAN. Scope FortiGate, SD-WAN. Aug 24, 2016 · Is it possible to specify a MTU value for a specific tunnel just you do for an interface? I don't think so because I think that the MTU settings is specific of a physical interface and not a virtual/ipsec one but just to be sure Oct 14, 2021 · In this scenario, the customer has a site to site IPSec VPN tunnel between two SonicWall appliances. Oct 19, 2018 · We noticed 3-4 years ago (possibly sooner) that on connection speeds with throughputs over about 40-50 megabits, when pushing data across an ipsec tunnel we see no more than about 30-40 megabits. Same result when using the IP address rather than host name. We are talking about 1mbits to about Problem : SMB/samba over IPSec slow – how to speed up? I’m running a samba-server at the headquaters, connecting to it with my Windows 7-machine in a remote office, connected to the hq through an ipsec-tunnel. HQ Up/Down speed is 250/250, but the shares on the DC are getting only about 50Mbit Upload/ 12 Mbit Download. Researching the issue, we found that a WAN accelerator is needed for the SMB optimization. Oct 7, 2021 · Very Slow Windows Server File Transfer Over IPSec Site to Site VPN Networking general-networking , question 2 1369 July 5, 2021 Improving IPSec File Transfers Networking discussion , general-networking , windows-server 4 303 October 28, 2017 ipsec site to site tunnel drops after 100MB circa Networking general-networking , question 12 205 May 22 Jul 24, 2023 · how FortiOS treats a packet which is about to traverse an IPsec tunnel interface, but the packet exceeds referenced MTU size. Feb 9, 2024 · I have an Azure Files premium account which I setup SMB multichannel. In IPSec, you can configure various settings, such as encryption and authentication algorithms and security associations timeouts. To eliminate the VPN you could set up a second FGT on site (via patch cable), create a IPsec VPN to HQ and then transfer via SMB. This is going to sound a little odd, but we have a case where we have an IPSec tunnel and need to implement QoS over the tunnel to not use more than 90Mbps total. No UTM policies on the VPN link. i have two sites: D and M with a wireguard tunnel between them. The Samba server is located in the Czech Republic, and its shared folders are accessed from Italy through the IPsec tunnel. We just set up a new location on the other side of the US. Feb 8, 2023 · troubleshooting for slow download and upload issues over the IPsec tunnel. If I test with a single file at a remote IPSEC connected site I get around Jan 27, 2023 · Use wan optimized Stuff to push Data over VPN, not SMB, it designed is lan ony. Jan 30, 2021 · Hello everyone, I am dealing with a packet loss issue with Site-to-Site VPN this issue is causing havok on the voip phone system. I’ve verified 1500 MTU set on the NIC, switches, and firewall… Jul 5, 2019 · Hi there, I found out all TP-Link router/modem supports LAN to LAN IPSEC VPN tunnel. SMB - Servers are Windows 2012, users are windows 10, and a few OSX. Although the tests above were conducted on the servers - so Win 2012 to Win 2012, over a network share. Solution SMB (The Server Message Block) is a client-server communication protocol using ports 139 and 445 with TCP. Sep 17, 2010 · Cisco Community Technology and Support Security VPN File Transfers Dropping over site to site VPN tunnels (GRE ove IPSec) Jul 22, 2025 · IPSec is a suite of protocols used to secure communications between peers. Aug 29, 2023 · 5 176 August 30, 2023 Domain Controller over IPsec Security firewalls , question 11 659 May 13, 2019 How to join AD while local firewall is your DNS server - multiple AD sites Software & Applications general-windows , active-directory-gpo , best-practices , question 9 208 April 2, 2018 An Active Directory Domain Controller for the domain could Mar 16, 2019 · SMB is a very chatty protocol designed for low latency local links. Jun 18, 2025 · To create a VPN tunnel over IPsec, you must create users who will be granted remote access and group them together. Branch office users are complaining The routers are tied together by an IPsec tunnel that pushes each subnet to the other site The setup has been stable on a DOCSIS 3 150mbits/up connection for some time with latency between the sites are around 30-50ms. Connected the users to it via an IPSEC tunnel. Nov 24, 2016 · Hi, we recently deployed a Win2012r2 Domain Controller in Azure and connected it over an Ipsec tunnel to our HQ (pfsense). This seems slow to me as I would expect double or triple that speed. Facts about network speed Network speed between two hosts is determined by the following: Bandwidth between two hosts: The maximum speed is achieved with zero latency and zero packet loss Nov 6, 2020 · The issue is that SMB is a block based protocol whereas HTTP is a streaming protocol. We use on both sites Slow Site-Site ipsec VPN My site-to-site VPN is slow. Apr 23, 2024 · We have a setup with two sites, each with a Sonicwall TZ500. Ping is 150-200ms. Feb 4, 2018 · Hi, So we've some strange behaviour with SMB/CIFS through an IPSEC VPN tunnel. When Overview This recommended read explains network speed, how to achieve high VPN speed, and how to troubleshoot slow VPN speed. The first thing I would verify is that icmp, especially pmtu, is working properly from each endpoint device (not testing over the VPN). However, the issue always seems to be related to the fact that broadcasts are not being passed over the IPSEC tunnel. I setup a test folder with 50,000 very small files. Is it possible to have a tunnel interface which can be used for GRE/IPSEC tunnel? Any future plan to support this feature? Thanks. At that time server 2003//XP and older versions of Windows was still common. what's the best settings and proposal needed for best performance and stability, while ignoring security? IPsec VPN over TCP on Windows, macOS, and Linux 7. How is performance between clients over the s2s to tunnel? Maybe try lowering MTU/MSS on the VPN tunnel, you have a lot of overhead on your packets, with pppoe, IPsec and then another layer of pppoe. The configuration looks very generic. It moves continuously from We recently took a dying SMB server (Windows 2008) from one of our customers, turned it into a virtual machine and moved it to a nearby datacenter. 3. Alternatively, use a different technology such as FTP or HTTP, as you mention, to get files on your local machine. Tristan. Instead of SMB/Windows shares, you could be using SFTP to safely exchange files from Windows shares over VPN connections. SMB (SAMBA) is an extremely chatty protocol and was designed for LAN use. I'm currently trying to use Samba over IPSEC (one site has monowall 1. I have in both sites FortiGate 60C and Ipsec tunnel between them. The exact threshold beyond which packets may be dropped depend on a va Apr 1, 2025 · Learn how to configure a site-to-site (S2S) VPN for use with Azure Files so you can mount your Azure file shares from on premises. 6. Mar 24, 2025 · The established IPsec site-to-site tunnel experiences frequent traffic drops; even though the tunnel stays up, ping and various other small packet services are fine. Main office has the AD and file servers with a brother TCPIP printer with a x. VPN should make the computers trying to connect appear inside your network. Both sites have 500Mbit links, and 40F IPsec throughput should be more than enough. This means, in tunnel mode, the IPSec wraps the original packet, encrypts it, adds a new IP header and sends it to the other side of the VPN tunnel (IPSec peer). Hence, tunnel mode provides better security by encrypting the entire May 22, 2025 · Hello, I’m reaching out for advice from experienced network administrators. 1-23n) remote office. A better bet is to use a different protocol for file transfers over the VPN link. Scope FortiGate. 9. Nov 3, 2022 · Hi all, Using Forticlient IPSec VPN to connect back to office network unable to access network shared Please help. Jul 28, 2025 · The speeds given are using iperf3, i am not talking about SMB speed tests. Use the Azure portal, PowerShell, or CLI. They Jul 4, 2022 · Description This article describes troubleshooting for the speed or bandwidth throttling issues over the Site-to-Site IPsec tunnel. 0/24, and client is trying to SMB to his printer for example). Transfer performance of a single large file averages at around 45 Mb/s. Dec 1, 2020 · A simple IPSec site-to-site tunnel to another location with specific advanced parameters like "Install policy" all let by default. The shared folder is only shared by domain PC. (Optional) Specify how the firewall will monitor the IPSec tunnels. Both sides are running FortiGate 61F and 101Fs with a complete Fortinet stack. Sure a tunnel does change some things, but SMB, which the OP was asking about, tended to be far worse compared what you would expect from simple benchmarks. Please note that the throttle only occurs for traffic that goes through the IPsec tunnel. There are two networks – one in the Czech Republic and one in Italy – connected via IPsec. You said you aren’t doing split tunnel, but curious if the remote network user is using is the same address space? (Server is 10. Solution One of the most common concerns is with the IP Jun 27, 2023 · When SMB Multichannel is enabled, the SMB protocol attempts to send the traffic across all available interfaces (including \GP adapter) which causes the performance issues. Running a large file copy between two Windows machines only gets about 40-50 Mbps even though one side is 1gbps/1gbps and the other is 300mbps/300mbps. I have an IPSec tunnel between two office locations with a Synology DS-918+ situated at the main site. With the increasing complexity of modern networks, it’s essential to optimize IPsec tunnel monitoring to prevent potential bottlenecks and ensure seamless communication between network segments. Any help with this would be greatly appreciated. In today’s interconnected world, sharing files over a network is common in many organizations. Tunnels are ADVPN IKEv2 with PSK. When I try to transfer files transfer speed goes in average 500kb/s but it not stable. Typically, the client profile is that they have multiple sites with site-to-site VPNs and a centralized file server. 10, and home network is 10. I’ve set the MTU on the wan links to 1320 to see if it Nov 27, 2017 · Hi, last time I had really slow SMB traffic over ipsec using a 100D, the support told me to disable asic and hmac offloading for ipsec: config sys global set ipsec hmac disable set ipsec asic disable end This "fixed" it for me, the traffic is now 6 times faster than before. Nov 23, 2021 · The debug output you display is just a reflection of your current configuration which doesn't give any information about potential TCP retransmissions due to lower MSS in the path. SMB transfers are slow, about 2 or 3mbps. Mar 7, 2025 · IPsec (Internet Protocol Security) tunnel monitoring is a crucial aspect of ensuring the security and performance of your FortiGate firewall. The VPN is configured in full-tunnel mode along with split tunneling enabled. 5Mbps [SMB transfers] BTest between MTs that when using both IPSec VPN and MPLS/P2P connection at the same time, users might notice that the transferring speed (of the same files) in the IPSec tunnel is usually slower than that of MPLS/P2P connection. Three Sites Site A - HQ Site B Site C A has a vpn tunnel to B and C B and C are also connected to a VPN Tunnel the vpns are IPSEC using IKEv1 when I ping anythi Optimizations that can help Windows SMB over VPN Longtime lurker, had a sleepless night where I decided to test optimizations for our RRAS VPN and wanted to share optimizations that have added up and made a difference. Hello fellow monowallers I know the issue of SMB/Samba/Netbios over IPSEC has come up many times. Both have Firewalls set up and an IPSec tunnel established between them. The reason is that VPN traffic is encrypted and its latency is also unpredictable over t Apr 5, 2017 · SMB doesn’t seem to be passing through the tunnel either. Conversely, if Site B cannot Dec 19, 2024 · 0 hescominsoon @planedrop Dec 19, 2024, 11:32 AM @ planedrop said in slow transfer speeds ove ipsec: @ hescominsoon SMB is extremely latency sensitive, so it's not really abnormal to see bad performance over something like a VPN. The layer2 traffic can be pass through, the server can ping each other on both ends, but when I trying to access the SMB or LDAP, it won't work. True or urban legend? (It would be a bit of a hassle to do this on the HQ side since I'm not there) Factory reset is The Server Message Block (SMB) protocol is widely used in enterprise environments for file sharing. I have a Windows 2019 essentials server domain controller which has been configured for VPN remote access. The tunnel status shows up and running but the traffic cannot pass through the VPN. ) of SMB over a site to site connection - and I’m on fiber on both ends. You can configure an IPsec VPN tunnel to use UDP or TCP exclusively or automatically switch to TCP mode if the firewall blocks UDP mode. I suspect a MTU/MSS issue however I'm unable to pinpoint the root cause. Hey, guys: I just setup the vlan in VXLAN over IPSEC tunnel between 100F and FortiVM with 2 CPU cores. ScopeFortiOS. Regards bommi Our data transfer speeds over VPN links are very bad. pfSense 2. Solution Whenever there is a slow speed issue through the tunnel it is possible to validate the throughput once with the WAN link and once with the tunnel link towards the same peer side. 0. If we turn off IPsec, we observe very good speed, as fast as ISP connection speed limit. 7. Wan link is 500Mb symetric at each site. Currently, workstations at the remote location are unable to join the domain that is on the Nov 17, 2022 · how to troubleshoot the slow file transfer issue with the SSL VPN connection. For the AirPrint, I can connect my iPhone to the VPN (I get an address on the same subnet as the printer) but cannot print. I can confirm connectivity between both sites. What transfer speeds you get on SMB ? I had best SMB speeds over wireguard with 1350 MTU, did you try that? I get near max speeds of wireguard tunnel it self. When sending I specifically use RDP over the site to site as to not rely on the transfer speeds (and potential dropped packets, lag, etc. This infrastructure is set up with two Virtual Sophos XG firewall appliances on both sides of the tunnel. 4. requires two or more Security Gateways with the IPsec VPN Check Point Software Blade on a Security Gateway that provides a Site to Site VPN and Remote Access VPN access. This uses UDP port 443 by default and provides a TLS 1. The server is centos with SMB shares setup. However, using Initially, IPSEC fragmentation was looked into as the file needs to be accessed via an IPSEC tunnel, but can rule out IPSEC being an issue as having copied this file to the network via an RDP session I get the same problem when copying the file between different VLANs in the same office over SMB. If you're Oct 15, 2020 · GlobalProtect SMB Traffic Slowness (discussion) GlobalProtect SSL VPN Slow SMB Transfers (discussion) Allow me to first explain why SMB is a bit of a special protocol and why it's behaving the way it is: SMB content is inspected differently compared to other protocols, like HTTP or FTP for example. The Linux-based NAS devices can still fall back on 139 (SMB 1) if 445 (SMB 2/3) fails, so they connect regardless.