Smb over ipsec tunnel. IPSec tunnel mode is the default mode.

Smb over ipsec tunnel AES256-SHA512. Feb 8, 2023 · troubleshooting for slow download and upload issues over the IPsec tunnel. 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. Main office has the AD and file servers with a brother TCPIP printer with a x. 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. This helped Mar 4, 2019 · Fortinet to Fortinet, 100E to 60E, IPSec Tunnel, gigabit connection on the 100E and 400mbit on the 60E. Tunnels are ADVPN IKEv2 with PSK. 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. It applies to all VPN types, such as remote access and site-to-site IPsec/SSL VPN. Monitoring VPN Tunnels This section describes how to monitor VPN tunnels. Feb 4, 2018 · Hi, So we've some strange behaviour with SMB/CIFS through an IPSEC VPN tunnel. I have a 500Mbps pipe on one end and practically unlimited (1Gbps+) on the other. 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. If your endpoint is in China, switch to a CN2 DIA. When I try to transfer files transfer speed goes in average 500kb/s but it not stable. No UTM policies on the VPN link. But if we try to copy any files via SMB on Windows machines – speed is extremely slow. 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. pfSense 2. i have two sites: D and M with a wireguard tunnel between them. 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. 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. Once you have a VPN connection, it is better to connect to a remote server and access the NAS from it. 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. SMB transfers are slow, about 2 or 3mbps. I'm having a weird issue with the IPsec VPN between two sites. Connection speed between sites is 15Mbps Down/Up (Speed is the same in both sites). In today’s interconnected world, sharing files over a network is common in many organizations. 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). 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. Feb 26, 2025 · some of the common factors affecting the IPSec VPN throughput and its limitations. This Speed is no problem for the 21er, System Load 8-9%, Interrupt 18%. Researching the issue, we found that a WAN accelerator is needed for the SMB optimization. Mar 7, 2025 · IPsec (Internet Protocol Security) tunnel monitoring is a crucial aspect of ensuring the security and performance of your FortiGate firewall. 3. In this Jul 8, 2019 · However, now I have two Tl-R600VPN routers successfully connect with a IPSEC site to site tunnel. 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. 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. 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. Try to change the MTU, if this doesn't fix the problem good luck. 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. 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. Feb 9, 2024 · I have an Azure Files premium account which I setup SMB multichannel. 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. 3) through IPsec tunnel located at branch (Watchguard). That will be affected by which DH algorithms are being used among other things. Scope FortiOS. 30 we observed better copy speed via SCP on linux machines. This uses UDP port 443 by default and provides a TLS 1. Packetloss would also slow down IPSec, so I'd go for problems on the line or the nic. Hello fellow monowallers I know the issue of SMB/Samba/Netbios over IPSEC has come up many times. This also allows transport mode to properly filter traffic in both directions, such as with GRE tunnels protected by transport mode IPsec. The only things I know to try are: Reduce the MTU in the tunnel interface associated with the ipsec connection. 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. 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. If there’s a deny rule at the end of the security rulebase, intrazone traffic is blocked unless otherwise allowed. 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. We have an SSL VPN configured on a FortiGate VM on firmware 7. May 13, 2024 · how to troubleshoot the slowness in SMB traffic transfer over FortiGate SD-WAN. 1 IPsec VPN, dependent on UDP, can run over TCP. 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. Meaning people didn't have SMB2/SMB3 which dramatically improved CIFS/SMB performance. 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. 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. 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. Both locations have 101F for the device. 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. ScopeFortiOS. e. 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. Apr 23, 2024 · We have a setup with two sites, each with a Sonicwall TZ500. Synonym: Site-to-Site VPN. Feb 9, 2023 · Solved: hello together I have the following problem over IPSEC VPN the file transfer to a share is very slow. Instead of SMB/Windows shares, you could be using SFTP to safely exchange files from Windows shares over VPN connections. 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. Solution The best way to troubleshoot speed-related issues on the IPsec tunnel is to compare the bandwidth over WAN. Although the tests above were conducted on the servers - so Win 2012 to Win 2012, over a network share. 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. . Use the Azure portal, PowerShell, or CLI. 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. 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. This is a critical problem, as Jul 21, 2025 · Scope FortiGate. 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. 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. However, the issue always seems to be related to the fact that broadcasts are not being passed over the IPSEC tunnel. 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. Once you can verify the Internet connection between devices, then check the same things inside the VPN connection. both sites have: hap ac2 with a NAS attached on LAN. Jul 13, 2015 · Hello! We have network issue with extremely slow copy speed via GRE or IPIP IPsec tunnel. Nov 22, 2022 · Hi Everyone-- I'm hoping someone might have a suggestion. 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. I have an IPSec tunnel between two office locations with a Synology DS-918+ situated at the main site. SMB file sharing works great on LANs but struggles with VPNs in hybrid work setups, causing productivity issues. There's also ways to see if the tunnel is using the ASIC NPU offloads or not. 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. 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. 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. We have a windows file server in Site 1, a Nas in Site 2. Nov 24, 2016 · Hi, we recently deployed a Win2012r2 Domain Controller in Azure and connected it over an Ipsec tunnel to our HQ (pfsense). IPSec tunnel mode is the default mode. Jun 18, 2025 · To create a VPN tunnel over IPsec, you must create users who will be granted remote access and group them together. Iperf shows 44 mbps. There are two networks – one in the Czech Republic and one in Italy – connected via IPsec. Scope FortiGate. In US site I have a file server which needs to be accessed from EU site. If I tranter SMB I’m getting around 3mBps showing from windows. The Samba server is located in the Czech Republic, and its shared folders are accessed from Italy through the IPsec tunnel. If we turn off IPsec, we observe very good speed, as fast as ISP connection speed limit. Currently we are facing issue when access or open a file located at File server (10. 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. Transfer performance of a single large file averages at around 45 Mb/s. This seems slow to me as I would expect double or triple that speed. Dec 1, 2020 · A simple IPSec site-to-site tunnel to another location with specific advanced parameters like "Install policy" all let by default. 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. DH 19,14. So I setup a site to site vpn (main mode, group 2, 3des,sha1. I can confirm connectivity between both sites. 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. 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. 5 on both ends. A better bet is to use a different protocol for file transfers over the VPN link. Tristan. Contractions: S2S VPN, S-to-S VPN. One such configuration is the IPSec mode—tunnel mode or transport mode. VPN tunnels were set up using the FortiGate VPN wizard template. Jun 13, 2019 · SMB is a LAN protocol and a pita on WAN. Mar 30, 2020 · Our company recently transferred to fully online from in office due to the current crisis. When Overview This recommended read explains network speed, how to achieve high VPN speed, and how to troubleshoot slow VPN speed. ScopeFortiGate, FortiClient. Solution The SMB protocol is designed for local file sharing with low latency. HQ Up/Down speed is 250/250, but the shares on the DC are getting only about 50Mbit Upload/ 12 Mbit Download. 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. After upgrade to latest firmware version 6. We all know that SMB is very chit-chatty so latency really kills the performance. 1-23n) remote office. SMB - Servers are Windows 2012, users are windows 10, and a few OSX. Mar 9, 2023 · troubleshooting for slow speed issues over the IPsec tunnel using the iPerf tool. Go to User & Authentication → User Definition → Create New. 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. Feb 19, 2017 · Hi all, I have two sites US and Europe. 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. Both have Firewalls set up and an IPSec tunnel established between them. (Optional) Specify how the firewall will monitor the IPSec tunnels. Therefore, it is highly sensitive to packet loss Oct 6, 2021 · I have been experiencing super slow transfer speeds over IPsec using SMB. And yes, if you use AES GCM with SafeXcel on ARM, you got stuck after som Time with the entire IPsec Stack. 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. thanks This is a known phenomenon. I suspect a MTU/MSS issue however I'm unable to pinpoint the root cause. 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 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. 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. 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. 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. Nessus flagged any system with it enabled and to disable it, then we did. 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. 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. 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. 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. I setup a test folder with 50,000 very small files. 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. 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. Aug 15, 2019 · We have fortigate 300E ( india office) & 100D (US office) both are connected via IPSEC tunnel. See Monitor Your IPSec VPN Tunnel . The VPN is configured in full-tunnel mode along with split tunneling enabled. 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. 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. To get a true performance test, run iPerf from Office A to Office B …. 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. VPN tunnels are up and we can ping devices on the remote network through the VPN. 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. 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. The shared folder is only shared by domain PC. 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. IPSec tunnel mode creates a secure connection between two endpoints by encapsulating packets in an additional IP header. 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. 9. ) of SMB over a site to site connection - and I’m on fiber on both ends. 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. We use on both sites Slow Site-Site ipsec VPN My site-to-site VPN is slow. iperf client and server on same lan network, no firewall involved: 900+mbps. 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. In the Czech Republic, there is a Mikrotik RB4011iGS+ router; in Italy, it’s hard to say. 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). 4. 2. This infrastructure is set up with two Virtual Sophos XG firewall appliances on both sides of the tunnel. 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. 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. Please help to put me back on tracks. 1. For example, our Cisco router provides IPSec / UDP and IPSec / TCP. 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. At that time server 2003//XP and older versions of Windows was still common. SMB (SAMBA) is an extremely chatty protocol and was designed for LAN use. 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. May 22, 2019 · SMB performance over VPN is an issue we see periodically at our clients. 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. 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. 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. Scope FortiGate and all FortiOS Platforms. I can ping IP, nslookup and ping hostname of the PC. We have a primary location with a Local AD server. 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. Both sites have 500Mbit links, and 40F IPsec throughput should be more than enough. The client pc is a standard windows 10 os. Best was with defauts. 7. 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. VPN Tunnels Solution VPN Tunnels are secure links between gateways. Wan link is 500Mb symetric at each site. Solution SMB (The Server Message Block) is a client-server communication protocol using ports 139 and 445 with TCP. 0/24, and client is trying to SMB to his printer for example). 3 MR-3-Build427) and machines on the other side of the IPSec S2S VPN tunnel. 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. This issue does not affect connectivity between local network computers and remote machines—only the firewall itself loses connection. Solution Packets that are too large may be dropped by Internet or private network routers. Connected the users to it via an IPSEC tunnel. 20. 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. ScopeFortiGate. The first thing I would verify is that icmp, especially pmtu, is working properly from each endpoint device (not testing over the VPN). 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. There is a pass any/any rule set up on both the LAN and IPSEC interfaces in the firewall rules section. 6. 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. The configuration looks very generic. Site B: Cisco RV340 with the same type of local setup, a LAN and a WAN leg. Both sides are running FortiGate 61F and 101Fs with a complete Fortinet stack. 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. These Tunnels ensure secure connections between gateways of an organization and remote access clients. Oct 26, 2021 · The tunnel interface for this particular site-to-site is also using default MTU. the NAS-NAS speed doesn’t exceed 5. Any help with this would be greatly appreciated. I’ve tried to figure it out and finally got confused, so my tests lost a structure a became a random lock-picking. 8-10o) main office to TZ400 (SonicOS Enhanced 6. We just set up a new location on the other side of the US. x. 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. 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. VPN should make the computers trying to connect appear inside your network. Also, not sure about NetBIOS as a comment or above me mentioned. SMB 1. 3b11 and the other has pfSense 1. Scope FortiGate, SD-WAN. 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. 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. Regards bommi Our data transfer speeds over VPN links are very bad. 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). The server is centos with SMB shares setup. When running SMB over slow, higher latency links you will get slow performance out of the VPN. We are able to open the shared folder using map|smb folder. 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. 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. 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. 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. 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. P2 esp,3des,sha1, enable keep alive & netbios broadcast) using sonicwall TZ300 (SonicOS Enhanced 5. Ping RTT between the sites is about 30ms. I run my NAS Backups over the Tunnel, with the Upload limiting around about 50MBit/s. I have in both sites FortiGate 60C and Ipsec tunnel between them. 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. I have a Windows 2019 essentials server domain controller which has been configured for VPN remote access. They Jul 4, 2022 · Description This article describes troubleshooting for the speed or bandwidth throttling issues over the Site-to-Site IPsec tunnel. Upload speeds are about 27 mbps Sep 26, 2025 · Hello, due to massive performance issues when using SMB over IPSec I tried Wireguard Site2Site. Turn replay protection off on both ends ipsec config. 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. Nov 3, 2022 · Hi all, Using Forticlient IPSec VPN to connect back to office network unable to access network shared Please help. 0. Please note that the throttle only occurs for traffic that goes through the IPsec tunnel. In IPSec, you can configure various settings, such as encryption and authentication algorithms and security associations timeouts. 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. We have a head office (60F) and branch office (40F) connected with a VPN. The speed fluctuates greatly and typically averages out in the KB speeds. 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. 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). 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. Solution When an IPSec tunnel is configured on an interface (i. If Site A cannot reach Site B, check the Site B firewall log and rules. Tunnel is up, icmp is working fine. With a continuous ping, if the RTT goes up 10fold during an SMB transfer then it's the upload speed issue. Typically, the client profile is that they have multiple sites with site-to-site VPNs and a centralized file server. The tunnel status shows up and running but the traffic cannot pass through the VPN. 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. IPsec over TCP can help VPN traffic pass through restrictive firewalls, especially when the firewall only allows TCP-based traffic. 10, and home network is 10. 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. Hey, guys: I just setup the vlan in VXLAN over IPSEC tunnel between 100F and FortiVM with 2 CPU cores. 10. 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. 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. Apr 15, 2025 · The Server Message Block (SMB) protocol is widely used in enterprise environments for file sharing. ScopeFortiOS. iperf3 client to server over the ipsec tunnel: 50-60mbps (regardless of what changes we make in the tunnels). Jul 28, 2025 · The speeds given are using iperf3, i am not talking about SMB speed tests. Seems strange that only SMB, and only SMB on Windows seems to be affected. Even a slight packet loss or delay in these exchanges can cause noticeable slowdowns. 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. Oct 22, 2019 · fortigate 200e. , 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. We currently are using a sonicwall tz400 for our firewall and the Global VPN IPSec tunnel for connecting to the office’s server. 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. Aug 11, 2024 · here comes yet another (i suspect) MTU issue. I'm currently trying to use Samba over IPSEC (one site has monowall 1. Is it possible to have a tunnel interface which can be used for GRE/IPSEC tunnel? Any future plan to support this feature? Thanks. Define Security policies to filter and inspect the traffic. 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. x subnet, remote office has a x. 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. What GRE/IPSEC tunnel you mean? If you mea L2TP over IPSEC VPN, TP-LINK SMB Router supports it. 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). The Linux-based NAS devices can still fall back on 139 (SMB 1) if 445 (SMB 2/3) fails, so they connect regardless. Hence, tunnel mode provides better security by encrypting the entire May 22, 2025 · Hello, I’m reaching out for advice from experienced network administrators. 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. The site A is connected to a 1G symmetrical fiber service and Site B is connected to a 500 Symmetrical fiber. 3-encrypted security tunnel like a VPN for the SMB traffic. 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. This chattiness results in a lot of overhead, and the VPN would have to encrypt and decrypt each packet. Ping is 150-200ms. Same result when using the IP address rather than host name. 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. The bandwidth over the tunnel is topping out at 56Mbits both up and down. Alternatively, use a different technology such as FTP or HTTP, as you mention, to get files on your local machine. 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. 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. saayri tnfamkt dtava vqhbnl bnzhf pqrxol oocsq xgwjh kfgpuvt elzjleo xqegwube iexm ybea wdthgb wngcr