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5
votes
1answer
138 views

POST of MTU + ~798 bytes gets lost

I have a very weird issue with certain packets not arriving on the destination host. It happens when we transmit a POST that is somewhat larger than the MTU. We can reproduce it with this script: ...
2
votes
1answer
265 views

MTU value causing applications to hang

I am using CentOS 5 in my environment and it acts as a gateway for my LAN. My eth0 interface MTU is set to 1500 (default). UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 Recently I am facing a ...
1
vote
1answer
203 views

Debian don't forward through L2TPv3 more than mtu l2tp virtual interface

R3--R1--Internet--R90 R3: ip addr 10.123.0.3 R1: sudo ip l2tp add tunnel tunnel_id 699 peer_tunnel_id 699 encap udp local 5.254.174.8 remote 5.254.174.90 udp_sport 699 udp_dport 699 sudo ip l2tp add ...
1
vote
1answer
1k views

How do I view cached PMTU under Linux (and all other OSs)

When I ping a remote site with the DF bit set and a packet size that is too big for my router the first ICMP "fragmentation required" message is sent from the router. After that the message comes from ...
1
vote
1answer
549 views

different MTU sizes for bond aliases

I have a bond interface but I want to change the MTU to 1500 only for bond9:22 Is this possible? bond9:22 Link encap:Ethernet HWaddr 00:0E:0C:E4:BE:F9 inet addr:10.7.18.58 ...
0
votes
1answer
37 views

Fragmented DNS Packet

The DNS response against my domain is 1228 bytes long and I need the packet to get fragmented in 3 packets. To achieve this I have set the MTU at name server (bind9 running on the machine) to be 500. ...
0
votes
1answer
34 views

Linux route cache seems to load outdated settings

On SLES 11 SP3 (Kernel 3.0.101-0.46) I see the following route behavior: When I set a route specific MTU once via ip route change ... mtu lock 1500, everything works as expected (setting an MTU of ...
0
votes
1answer
64 views

IPsec transport mode and MTU

[Similar to Right way to set the MTU of an IPsec Client (Linux/Racoon), but different in that there is no router on the responder side] I have a setup where machines in a local network need to talk ...
0
votes
1answer
227 views

CentOS 7 MTU setting not works

I am using CentOS 7 to test some network performance. The interface setting is normal like that : saberin@localhost ~]$ ifconfig enp0s25: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ...
0
votes
1answer
46 views

Finding network type using MTU

For example MTU of Ethernet is 1500. Now if the packets are fragmented, then observed MTU will be the MTU of the router (i.e. less than 1500). Is there any method to find out the type of the client ...
0
votes
1answer
646 views

Under FreeBSD, can a VLAN interface have a smaller MTU than the primary interface?

I have a system with two physical interfaces, combined into a LACP aggregation group. That LACP channel has two VLANs, one untagged (the "native vlan") and one using VLAN tagging. This gives us: ...
-1
votes
1answer
182 views

VMWare - Jumbo Frames over iSCSI to a NAS4Free array

I am having problems getting Jumbo Frames working over my iSCSI connection. Here is what I try. 4 1GbE connections on 4 different subnets on my NAS4Free array for iSCSI, MTU set at 9000 2 redunant ...
1
vote
0answers
58 views

Can't mount read-write iSCSI with MTU=9000

I'm attempting to connect my desktop (running debian 7) to a QNAP NAS (running QTS 4.1.1) using iSCSI with an MTU=9000. The network infrastructure consists of a cat5e crossover cable between the ...
1
vote
0answers
85 views

MTU on mobile data networks

I found various lists of MTUs for different links, but they never contain UMTS, LTE, EDGE, HSPA, GPRS. What are the MTUs of the above mentioned technologies?
0
votes
0answers
91 views

Right way to set the MTU of an IPsec Client ( Linux/Racoon)

Here's the network topology : (PC1:IPsec Client)eth0---Internet CPE---((Internet))---Internet CPE---(PC2:IPsec Server) I've set up an IPsec Internet Gateway : PC1 sends all traffic, encrypted in an ...
0
votes
0answers
113 views

Pptp Vpn: buffering packet .. (expecting .., lost or reordered)

System log is full of such messages. AFAIK this can be related to MTU size. ppp0 negotiates a MTU of 1396 with the ISP. I've tried so far: ip link set dev .. mtu 1396 iptables -A FORWARD -i ...
0
votes
0answers
122 views

xen routed networking maximum segment size

For a few days now we experience issues with xen in routed networking mode regarding the MTU and MSS values (xen 4.1, debian wheezy, ISP is Hetzner) (network-script 'network-route netdev=eth0') ...
0
votes
0answers
132 views

Severe performance issues sharing openvpn client connection to LAN clients virtualbox

I am trying to set up an internal network in Virtualbox in order to share an openvpn client tunnel with multiple VMs acting as clients that should be completely isolated from everything except for the ...